I have 20'' utopia for 2 years now. I think you would not feel any difference, i've had 19.4 flybikes tierra, few 20,75'' and 20,5 frames and i have 19.25 khe a-damn in my second bike. I've felt some differences but 19.4 and 20 with basic flatland tricks feel the same for me, but I've felt a lot different doing bunnyhops. Dropouts are bad as DaddyCool said, i had to ad chain link few times because pegs were leaning on the chain stay. I've never had problems with seat clamp, I weight over 100kg and i do a lot of hang 0 but it never slipped. I'm riding on autum bent fork, odyssey lincoln 53mm stem and autum narcobar 8.7''.