The control system is much better than Eden. Picked it up right away. Love the auto-jump (automatically jumps you up to the next block) which makes going up hills just as easy as going down them. Tap to place the current item, touch and hold to mine. On screen Dpad moves you, scroll with finger to change direction/view (like the mouse does now).
World is not infinite. It's quite large though (big enough for most any huge, ambitious building project). I've only looked at one world so far and it had normal, desert, and snow biomes.
Looks good on my iPad2/ios5! NO lag. $6.99 is a tiny bit pricy compared to other apps, but it's still worth it (to me).