2020i is easier to drive, has more prodigious bass output.
2010i needs an amp with plenty of power - they work ok on lower powered stuff but only really come alive on the end of something with lots in reserve.
I prefer the little ones tbh - they're more nimble, neater and just seem to have more energy. Stunning little speakers, but with the caveat that they're not just plug'n'play and need some careful setting up to really sing. Stands - I tried mine on Something Solid SL24's, heavy Target (30+kg) ones but the Q stands worked the best.