You'll lose XBL access.
Xenon models (2005-2006,the non-HDMI models) and Winchesters (some redesigned Slim models) can't really be RGH'd.
Other then that, yes RGH it.
That's not correct, only Winchesters can't be RGH'd.
Can't really.
There's a difference between can't and can't really.
Winchesters can be RGH'd with a 0fuse CPU swap.
Xenons can be RGH'd but it's unstable and honestly not worth it other then DVD key rescues.