We've been talking about it in the CPS2 emulation thread.
Its awesome and works great. I've already converted a few of my PSX games and fixed the saves for them. Awesome.
It's like the second golden age of the PSP. Firmware is much cleaner now... no need for renaming programs or kxploits, homebrew works as well as standard 1.5.. its great. If you own a PSP and are capable of flashing... do it now.