I just took my iphone game and got it running on the psp in 1 day with no prior psp knowledge. it looks alot better and easier for coding games than the stupid iphone with its objective c shit and crappy implementation of openGL!
also, the psp's debugger actually seems to work, you have to remember there is a good reason the apple sdk is free.. cause its buggy as hell!
and what do you mean "not having UMD would suck" ?? not having multi-minute load times will 'suck'???
and another thing, the apple sdk isn't free! you need to buy a Mac (which no self respecting coder would have) and pay $100 A YEAR, just to have your app rejected for no valid reason!
One question tho, having the sdk free is all well and good, but what about a dev kit? will we be able to use any psp as a dev kit like we do with the iphone? will there be an emulator?