Besides upgrading for PSP game compatibility, upgrading will give you access to the PSN, and give you access to another version of POPS. If those don't matter to you, then there's no reason to upgrade. The 6.60 version of POPS I've had the least amount of problems with. It's still not perfect, a few games will have slow downs and whatnot, but POPSLoader gives you the best of everything.