well with CFW 4.21:
you dont need an update to play new games
dont need a formatted BDEMU drive
Should be able to play Bluray movies
Dont need to convert EBOOT/SPRX/ETC to fself
Dont need patched EBOOT/SPRX/ETC until games higher than 4.21 are released.
Dont have to convert pkgs to dex
Do have write priveledges to Internal drive and play from Internal drive
PSN and eventually reactPSN support (Rap2Rif should work now as its a PC app not homebrew like reactPSN)
No playing games from LAN/PC
No Debug options
No discless games (as of now correct me if this has changed)
Homebrew wont work until resigned to 3.60 (not a huge deal give it time)
Prolly more stuff im forgetting just tired.
PS3 Slim 4.21.2 Rebug REX 4.31 Spoof (external 1TB/3TB), PS2 Fat w/ Internal HD