Some people here might be interested in the sweet potato tastings I've done over the years. I've grown at least 12 sweet potato varieties each of the last 8+ years and have done mostly blind taste tests with 5-8 tasters most years but with additional random friends and customers other years, including one year with over 20 customers, and always getting tasters to fill out "score cards" for me. Altogether, from the different years, I've probably gotten 50 different people to taste 10+ varieties together and rank/score them for me, some of those 50 people multiple times, so probably around 100 total score cards. What I find most notable from all these tastings I've done is that no one ever prefers any of the most common type of sweet potatoes sold in the stores (Covington or Beauregard or other varieties with similar flesh color and texture like Carolina Ruby...) when tasted side by side with other types. I've come to believe that a lot of people have false ideas of what they really like. In other words, people express a lot of different ideas about what they like until they taste the different varieties side by side, and then people show a remarkable degree of agreement about what they like.
All of the tastings I've done are based only on plain baked potatoes I've grown in my location, with my post-harvest storage practices, etc., so I have no idea how well they'd translate to different climates, different soils, different post-harvest practices, different cooking methods, etc., but I wouldn't be at all surprised if they varied a lot. I suspect, for example, that some big differences I've noticed in potatoes of the same variety grown the same year all on my small farm are due to having grown them in two different locations on my small farm where the soil type varies some.
So based on the taste tests I've done, it seems like Porto Rico and Nancy Hall (which I consider very similar types with similar texture and pale orange/yellow flesh) are universally liked. 21 of 21 customers last year, for example, gave Nancy Hall the highest mark on the tasting sheet. Other years Porto Rico has edged out Nancy Hall, but in terms of taste, I just consider them both very similar. I think the taste is outstanding. Even leftover at room temp with no salt or butter or anything else guests that taste them are frequently wowed by how great they taste, especially if they've previously only been familiar with standard grocery store types.
In that same taste test, only 4 customers gave Covington (the most common variety in stores today) the highest mark, which was fewer than all but two other varieties (of 13 total in that tasting). I will say, though, that although I think standard grocery store type sweet potatoes make very unexciting baking potatoes, they do seem to make the best sweet potato chips (deep fried) because of their texture.
Here's how I'd characterize the tasting results some of the other varieties:
McDaniel White - very good, very widely liked (softer, moister white fleshed variety)
Also widely liked and particular favorites of people preferring a firmer, dried textured potato with very good flavor:
Red Japanese (red skinned, white flesh, especially slow to age/cure/develop full flavor)
White Triumph (light skinned, white flesh)
Murasaki (similar to Red Japanese but I haven't trialed it as extensively yet)
Darker orange fleshed (relative to Porto Rico and Nancy Hall, for example) varieties that have been more variable in taste (maybe due to soil type where they were grown?), sometimes tasting great, other times just very plain, moist but not baby-food texture:
Varieties that people have liked well enough but haven't scored quite as high in taste tests:
Norton (light skinned, white fleshed, fairly moist)
Liberty (the most beautiful potato I've ever grown, purple-red skin, yellowish-white flesh)
Varieties that were another notch lower (mostly not disliked, but scored below average):
And at the very bottom are both of the purple-fleshed varieties I've tried growing. They're pretty much everyone's least favorite potato to eat plain. I don't think they were bad, though, just very, very plain compared to other potatoes.
I grew an additional 6 new-to-me potato varieties this year that I'm waiting to make sure they've had plenty of time to develop their full flavor before I taste them: Kotobuki, Suwan 147, Xushu 18, PI 267946, White Bunch, and TN Red. Those are mostly favorites of a friend that grows almost four times as many potato varieties as I grow.