We've had this for the Wii and when we got a pair of PSPs for travel, this had to be one of the games in the new PSP library.
Excellent play, lots of problem solving as well as many chances to completely trash little figures that reassemble themselves. The general concensus is that Poison Ivy is the top character, but YMMV. Both my son and my husband enjoy this game so much we'll have to buy a second one so that we can play against each other.
LEGO games never disappoint. I only wish we could get Batman 2 for the PSP.