Updating this thread to let people know that Cliff England has some rarer Pawpaw varieties in stock:
Maria's Joy--Davis x Prolific cross, formerly well known as 166-13. This seems to have a solid rep among aficionados because of size, a mild Tapioca/mango flavor, and good production.
250-39--Sunflower (low key...good proven quality with a bitterness issue with some of the fruit)x Sam Norris 15. Very large fruit that's closer to banana in taste. Much less data out there among forums as to how well it performs.
Halvin--wild seedling from way up northwest. Seems to be pretty good, but hasn't really been in the hands of enough people yet to know. Its proponents talk up a pineapple note.
Large grafted specimens (3'-5') are available for Davis and Rebecca's Gold.
So far as I have dug through comments...
Rappahannock--supposed to be easier to harvest with leaves away from the fruit and a little coloration. Very mixed reviews out there.
Allegheny--successful variety that grows well and gives more than acceptable quality fruit. Needs some fruit to be removed for size, and it's relatively seedy. Very much dooryard rather than orchard pawpaw.
Shenandoah--Has good market acceptance due to mild and smooth taste.
Potomac--people seem to be happy with this one, low key, but has been consistently overshadowed by other varieties. Fruit split an issue?
Wabash--clearly the best performing Peterson variety at this point. Good health, large fruit, good taste, good production. Have seen mention of one person managing to get fruit from a solo tree of this.
Susquehanna--suspect that this variety exists because it has the best potential fruit. Not that all or most of the fruits reaches that potential. However, this one probably should be notorious for dying off. LOTs of mentions of dead Susquehannas online. All of the Peterson varieties are a bit low on the vigor department, and this one is the unhealthiest.
Mango--good flavor, potentially better for the south than most varieties tested out further north in the Midwest. Vigorous tree, watery fruit that people may feel as slimy. Fairly tropical flavor on the spectrum between mild and exotic.
Atwood--A KSYU (Peterson was involved, though) variety that hasn't really had enough reviews online. It's probably pretty good, but should be noted that a seedling of this varietal, 250-30, has been specifically licensed out to the Far East as a premium variety. Perhaps improvable? In any event, it's sort of like Rappahannock in which ease of harvest is an important feature for commercial orchards. Also notable, KYSU obviously has about four more varieties that are notable that they just haven't made an effort to publicize. Makes one wonder.
Of the old varieties...
the two main ones are Overleese and Sunflower, as both are capable of generating enthusiastic approval for their fruits. Then NC-1 and PA Golden. Most of the rest aren't as systematically selected for strong advantage over wild strains. IXL (Overleese x Davis) does seem to have a little backing, somewhere back there.
New stuff not already mentioned...Mind you, very little spread of variety, and not nearly enough comments to really know what's what...
VE-21--Prolific x Overleese. Best appeal is early season high quality fruit.
VE-9--Prolific x Overleese. Not much to say other than large fruit, late, high quality? Definitely not widely planted as of now.
166-20;166-66, both are Davis x Prolific, with advantages in sweetness and yellow fruit color for easy of ripe detection and marketing. Probably mostly just significant for breeding.
250-30--Atwood seedling. Very large fruit with good flavor. Tricky to get with licensing issues.
275-48--Prolific x Sam Norton-15. Low key, seems to be one of the top new varieties. Very large fruit with good flavor. Again, not widely planted yet, so no surety on just how high quality it is...
275-50--same as above, seems to be a bit lower on the quality.
Of course, there are newer casual selection like Kentucky State Champion, Summer Delight, and the like, but they haven't really been tested so far as I know.
Seedlings have a success rate of about one in five seeds sown. Defects generally include seediness, poor texture, funky taste, bitter aftertaste, size of the fruits, vigor.