Depends what u want to customize....if you want to customize ur homescreens, there is no need for rooting, but if u want to customize ur notification bar and other things like that, you have to root, so even if Jelly Bean came out, u still will need to root to customize those other things
This is exactly what I'm looking to do, and I know I would still have to root I'm just wondering would it be less future headache for me to wait or if it'll be relatively straightforward to upgrade once I do root and mod, don't plan on flashing any ROMS yet as far as I can tell
Sent from my Red GS3