The game itself is awesome, but technical issues have prevented forced me to stop playing it. For me, it's love-hate.
If it weren't for the fact that it randomly crashes, forcing my PSP to shut-down AND corrupting the profile, I'd be scoring this game very high. Alas, despite several calls to Ubisoft support and searching for downloaded save-games to get by the crashy spots I have finally given up. *sigh*
The controls take a bit of getting used to a first but they quickly became reasonably natural for me. The camera was a bit wonky as many people have mentioned, but I didn't feel this was a show stopper. The AI is not particularly clever but for me this helped balance the unavoidable challenge of the PSP controls.
I'd love to actually play this game all the way through. I've picked up both Syphon Filter games. Hopefully I won't have the same kind of problems.