I've put around 10-15 hours into this over the last week, and I am loving it.
The story is definitely not GOTY material, but it's better than the original PSU plot. A lot of classic PSU characters make guest appearances. The lobbies/city areas have been replaced with static navigational screens, but I don't really mind.
The leveling feels accelarated when compared to the console versions. I said fuck it to my trial version character (level 20) and started a brand new one. She's already level 25 with a Hunter rank of 10. I'm currently ranking up Force.
The PSP control scheme fits well, but it takes a little while to get used to it. Especially if you have big hands. I still get a little awkward when it comes to using RB and LB abilities.
Visually, it's pretty impressive for a PSP game. It looks almost as good as the PS2 versions of PSU. I got used to it very quickly, and didn't even think about it anymore until I played PSU on 360.
It's a very solid game, well worth the $39.99 price point.
If you only ever played PSU at the very beginning and weren't entirely enamored with the experience, definitely check this one out. It's got all the original content plus the Ambition of Iluminus expansion stuff/improvements.
Now if I could just get some local friends to play it with me over ad-hoc.