Beginning now, July 28, 2019, I'm sharing some of my observations with growing grapes here in the San Diego area since the early 1990's, with emphasis on home garden growing.   I only grow grapes with seeds, -  to me with-seed grapes have a more nutritive feel to my body,... apparently a more nutritive effect on my body.  These are all grown with reference to fresh-eating.   In order to have grapes which aren't overly sweet, having them grow with part shade, such as half day sun, or, pergola style growing, or, fruit shaded by the leaves (but not touching or overly crowded or dark) so they're not getting direct sun on the fruit, or just dappled at most,.... those situations keep the fruit so they don't get overly sweet, but still nicely sweet and well flavored.    I'm not involved with wine-concerns:

Growing notes:  To optimize fruit quality and consistency of bearing abundant crops each year, it's preferable to have one bunch of grapes per vine-shoot.   In some cases, on some shoots, two bunches is good, and rarely three bunches is ok.

Below is a listing of varieties I've grown and grow and their description from my experience, and which you can compare and contrast with information by others online, and potentially eventually your own experiences:

Alicante Bouschet:  a dark red flesh and juice medium size grape with a nice medium berry flavor, relatively moderate sweetness for a grape.  Basically disease free in most open exposure growing situations.    Abundant producer.  Excellent fruit for fresh eating by classical/soulful standards, not modern big grape standards.   Does well inland, and probably by the coast in a warm sunny spot.   Basically disease free.  Likes clay-loam soils.

Cayuga:   Good vigor.   Resistant to disease.  Very productive.   Light green to greenish yellowish when ripe.   Well balanced sweet tang on the early side of ripeness,  but otherwise I find it too sweet, so, I don't recommend it.  Maybe the fructose content is 'too high' for nice balance.   A little more intense flavor than Ontario, but not as 'flavorful' as Ontario, if that makes any sense.  I prefer Ontario of the two, Ontario being a bit less sweet, less intense, nicely so.    Cayuga is a bit more tannic and tangy than Ontario.   Ontario has a more 'clean and fresh' flavor, if that might make any sense to you.    Skin a bit thicker than Ontario.   Medium size round fruit.   Grows well in all diggable soils.   Grows well by coast.

Dattier St. Vallier:   Nice neutral grape flavor, with nice crunchy seeds, very satisyfing.   Large egg-shaped fruit, distinctive shape, medium to large.  Green-ish-yellow color.  Basically disease free vine and clusters, if pruned adequately each winter, - as is true with grape vines in general.   Leaves pale colored.  Late summer ripening. Seems to need clay-ish soils for good vigor on own roots, otherwise grows well grafted onto other grapes / grape-rootstocks, such as grafted onto Alpenglow and Esprit.  Seems not to grow so well on Isabella/California-Concord, whereas New York Muscat grows and performs superbly on Isabella.   Tends have some yellowing older leaves more so than other varieties, but overall it does nicely.

New York Muscat:   Kind of a vanilla-muscat-labrusca-sweet flavor and fragrance.   Ripens beautifully.   Basically no splitting fruit nor any disease.   Grows more and produces more if grafted onto Pierce's Isabella, and also Golden Muscat, compared to growing on its own roots.

Price:  Not much fragrance, mostly a neutral plain flavor with maybe a tad of labrusca/Concord type flavor, rather sweet with some tang, so-so quality.   Round fruit.  Moderate vigor to vigorous.    Mainly a vinifera/labrusca hybrid, with some other species ancestry, medium size fruit.   Dark blue/purple/burgundy skin (aka blurplegundy).  Pretty much disease free. Typically no split fruit.   Early ripening, mainly July, June earliest.   Very productive.  Grows well in basically all soils.

Golden Muscat:   Vigorous to moderate grower, pretty much disease free.   Fruit rather susceptible to splitting, but, case by case situation, splitting is not consistent in occurrence, whether with nearby water or only minimal ambient water / dry circumstances.    But, for best resistance to splitting, and possibly no fruit split, that will most likely occur where the vine doesn't have lingering moisture during summer time (including reachable substantial deeper ground moisture), but, with a well developed root-system from at least two years of growth, and, with any watering being stopped by June at the latest, the fruit should turn out well, without splitting, for a late August through September ripening time.   As with most grapes, does not need full sun for good grapes.  Fairly drought tolerant, not needy.   Light green/golden colored skin.  Large somewhat elliptical fruit, not round.  Refreshing tangy sweet flavor, juicy.   Very productive.   Grows well in basically all soils.   Grows well by coast.

Ontario:   Beautiful mild labrusca flavor with other pleasant subtle flavor notes.  If grown on own roots, grows best in clay/clay-ish soils. Moderate sweetness, a nice lite honey flavor with some suggestion of apple flavor.  Moderate vigor.  Best grafted at least in some situations, especially when grown in sandy-ish soils, in order to have much more vigor; grows better on its own roots in more clay-ish content soils than sandy-ish soils.   I've grafted it onto Muscat Hamburg growing in sandy-ish soil, on which the Ontario has grown and produced very well.    Susceptible to leaf burn more so than other varieities, but still worthwhile enough and otherwise pretty much disease free.  Light green fruit, potentially a little golden when very ripe.    Medium size round fruit.   Very productive if grafted onto strong rootstock.  Grows well by coast including highly productive in cool winds. 

Pierce's Isabella (aka California Concord):   dark blue, moderate Concord type flavor with suggestion of some strawberry flavor.   Performs well basically everywhere.  No fruit splitting, no disease, good vigor.   A top choice.

Muscat Hamburg:  Good vigor, resistant to disease, good productivity.   Black fruit a bit elliptical rather than round.  Has to get fully dark colored, and will eventually lose acidity and tannic quality to be pleasant to eat, with modest muscat flavor.   Grows well in basically all diggable soils.   With adequate water the fruits plump up nicely, with moderate sweetness, lite muscat flavor,... having a beautifully balanced flavor.

Muscat Ottonel:  Good vigor, resistance to disease, good productivity.   Light colored fruit, basically colorless.   Ripens easily, nice muscat-rose-scent flavor.  A lovely grape.   Medium small compact clusters of medium to medium small sized grapes.   Grows well in all diggable soils.   Should be grown out of cool winds otherwise will be low productivity.  Grows well by coast with protection from winds, for the matter of fruit production.

Semillon:  Prefers clay-loam soils, so it seems.    Basically disease free.    The grapes, which are small to medium, are basically too sweet, cloyingly sweet.   Best with much cluster thinning.   The vine health is similar to Alicante Bouschet, both highly disease resistant.   Alicante Bouschet is way more interesting and balanced in flavor as a fresh fruit.

Verdelet:  Good vigor,  basically disease free, very productive   Light glassy colored fruit, basically colorless.  Basic pleasant grape flavor, nice, a little tang.  It's a 'lite' type of fruit character, lite n juicy, modestly/moderately sweet.  Grows well in all diggable soils.  In some location-situations can have substantial fruit splitting relative to other varieties which don't or very rarely have some fruit splitting, - and so probably best to grow where it doesn't get signficant ambient moisture within a month of fruit ripening or else much of the fruit will likely split.    I wonder if a substantial infusion of potassium into the root system would make it more resistant to splitting.

Alpenglow, Esprit, Swenson White:  In some locations, some years, all three are susceptable to a leaf disease which discolors the leaves with yellow and necrotic tissue which resembles photos of Esca-disease.   But, in other locales/areas/regions, they do fine without those problems,... and with some years no incidence if in the same locale, - so it seems with some few years of testing.   The affectation occurs in the late-spring and will last through the leaves dropping off in summer or the leaves being stripped off in summer, which then can prompt new-growth to occur which may not be much affected by disease,... although the disease and lack of leaves will delay fruit ripening about two months, with ripening depending on the new disease free leafy growth which grows out after the leaves have been stripped off (better to strip off the leaves, for the sake of aesthetics).    Or, maybe best bet, don't grow these varieties.   But, could be a location/case-by-case circumstance with the disease.   Read Lon Rombough website for descriptions of these three.   Btw, Swenson White has not allowed 'takes' in grafting attempts on it with three other varieties, whereas Alpenglow and Esprit have worked well as roostock, especially for Dattier St. Vallier.