I started DAO originally on the xbox (didn't have a PC at the time that could run it). Now that I have a new desk top, I repurchased DAO a year ago, and am spoiled by all the mods. Having said that, I will give you a quick rundown on the differences, that I have noticed.
1) Graphics. Simply put, not terribly pretty on the xbox. It never really bothered me (except for the dwarf teeth...yeesh!), but it is somewhat noticeable. Especially if you are used to running texture mods and the like...
2) Bugged dialogue. Until I got DAO for the PC, and loaded a handful of mods that correct some of the dialogue/banter bugs, I didn't know what I was missing. Since you came from the PC version (and possibly run mods that correct for bugged dialogue), it might be quite noticeable for you.
3) Gameplay. If you have ever played vanilla (no gameplay mods), then it should be fine. It isn't as finely tuned as on the PC (at least from my point of view), but setting up tactics, micromanaging, using talents, ect.....not much difference.
I still had a lot of fun with DAO on the xbox (and I got to chill on the couch, while playing....not a luxury with the PC. At least for me.), but then I did start with the console version. I think you can still enjoy it though. If it has been some time since you played "vanilla", then it might feel new again. *shrug*