Yes, I searched google, but I want to know which one is the best.

What does it do?

Downgrades the PSP to ver. 1.5 so you can download homebrew games.

you can do homebrew now on 2.00 to 2.60. you need GTA: LCS though. For a downgrader though, use MPH's.

I don't really think it's necessary to downgrade. The newer updates fixes it all, right?

The new updates past 2.60 are pointless. DO NOT GO PAST 2.00 UNLESS YOU ALREADY ARE. 1.00 and 1.50 are the best firmwares because they can do all homebrew and almost everything 2.00 - 2.60 can do. Don't even think about going to 2.70 or 2.71

I had to download my friends 2 psp's to emulate them but it was totally worth it.