Ultimately, you will not and cannot find a better PSP experience out there. Ready At Dawn has kicked the bar into the heavens in terms of what has done to achieve maximum processing power from the PSP. Of course that's not to say someone else couldn't come along and do the same. In fact, PSW are hoping that other dev teams will look at this PSP pinnacle and try their hardest to replicate the sheer scope and look these guys have achieved.
And after playing through this bleak, bloody bastard of a game you're going to be gagging for the inevitable arrival of the awesome God of War III next year. All kneel before Kratos!