When we have no ice (i.e., now), I skate on PICs weekly at a roller rink. I prefer the smooth floor to the unexpected surfaces/objects found outdoors.
They ARE different from ice skates. Friction is higher for one. It's also very difficult to do hockey or dance stops because the edges don't slide - they stick.
Still, I can do about 75% of the things that I can do on ice. I do three-turns, brackets (well, some of them), jumps and spins on them.
I've got a couple small video clips on the web showing some PIC skate moves (spin and double-threes) at the top of this page:
http://www.afterness.com/skating/movies_and_pictures.htmlThere are two things that stick in my mind about PIC skates 1) the friction is higher, so I must work harder. To do that, I instinctively go down deeper in my knees. When I get back onto the ice, I can use that practice and new-found muscle to significantly improve power and speed.
2) Three turns, brackets, and spins are all considerably more difficult to do on PIC skates. Practice them anyway, because if you can do them on wheels, they become easy on ice.
A nearby rink has an adult-only skate session once a week. I've become good friends with the regulars and look forward to a change from toddlers and teenagers generally found on ice freestyle sessions. The friendships developed are now as important to me as getting to practice.
You'll also find that indoor rinks greatly extend wheel and toe stop life. Back when I started on PICs, I wore out a new pair of wheels in only one long outdoor trip on a bike path. The "inside edges" were ground away from stroking. There are harder wheels designed for outdoor skating, but they slide more. I found the indoor rink better suited for what I wanted.