Admittedly, at this point, I have only had a few. Your basic standard entry-level items, (which count as sours on untappd): Dogfish Head’s Festina Peche, Moa’s Breakfast, Some Bruery selections – but I have noticed a common taste profile. They all taste and have a mouth feel of a really enjoyable Champagne.
One that falls in between say an Extra Dry and a Brut. Meaning Tart (to varying degrees) but still have just a hint of sweetness, and all were dry crisp and refreshing. Meaning something you drink the entire glass of and not burn yourself out on after a few quick sips. I have yet to pick up on the vinegar notes people talk about (though wine like flavors are quite common, so I see where the taste could go).
I am rather excited to delve deeper, as they seem to be a style I can get into: Off the beaten path, not bitter, complex, and not to forget: quirky as anything. Look for further entries in the Sour styles coming soon.