i like to upgrade my froyo to GB rom,
rooted my froyo for a while ago.
i am not sure which one to use and back up rom; rom manger or nandroid?
I think you mean should you do the nandroid backup through the 'Backup Current ROM' menu option in Rom Manager or just boot into recovery and do it through CWM?
I've done both and haven't noticed any difference. But I'm now just booting into CWM and doing it through there just because I have had an issue or two with ROM Manager in the past with flashing, etc.
Was that directed to me?
If so you're right...what I meant was, don't use ROM manager for anything but downloading the ROM. Do everything else with CWM.
In fact, I never use ROM manager even to download ROM's, I prefer to just download to my computer (it's a Macbook...don't hate me), and transfer to the SD card with old fashioned USB cable.