How's this even different opinion:
Rollerblading is easier, because you probably have your own rollerblades and keep them in good condition (wheels not worn out severely)
For ice skating, more people than not rent the skates at the ice rink... the skates are cheap quality (thus the hurting feet because of more pressure on the center of the foot, like walking on a tight rope), and the blades are rarely sharp enough to give you a good edge.
However, if you cast aside equipment issues, ice skating is easier. (at least for me, because I could ice skate backwards really well). It also takes less time to master stopping on ice skates- you can stop a lot faster than on rollerblades - do it the way hockey players do it. Plus, if you goof while stopping in ice skates, you just go sliding on your side across the ice, without falling down too hard... If you goof stopping on rollerblades, it's a more sudden fall.
And, (speaking from experience), learn in hockey skates... there's nothing worse (trust me) than trying to catch your balance and falling down backwards landing on your heels while wearing figure skates. Note: I said landing on your heels. Look at figure skates... the blade sticks out an inch or so like a, umm, bayonet. Ouch.