They're both easy with a little bit of practice
I'd say ice skating; I've done both. And, I've fallen on both... ice hurts more!!!
Ice skating...good luck on getting back up through the broken ice on your own
I try and avoid standing on wheels.
Ice skating as its on a blade with roller skates u can use quads which I think give balance
I find ice-skating much more difficult. Balance on 4 spread out wheels is much easier than a narrow blade