It's not bad at all. I did it over wifi and went to a different floor than the router. Nothing wrong with the play control at all. The buttons were really responsive. Although, it did freeze for about 10 seconds. Still, the ps3 isn't optimized for it so I would imagine the ps4 will do it better.
There are 3 options for the controller. Couldn't really figure out the first one although I will try it later. The second option was to hold select while pressing the shoulder buttons for R2/L2. Whoever came up with that idea has an IQ of 4. You practically need a stylus for the select button.
The 3rd option was to use the top right corners of the back as R2/L2, and the bottom corners as R3/L3. I would like to practice with this as I think I can get used to it.
Anybody know what other ps3 games support cross play? I want to go through a full game like this. If nothing else, I can share my experience for anyone interested.
Edit: found it. http://en.wikipedia.org/wiki/Remote_Play