nUI does not have all of Grid's features (yet) though I hope to entirely eliminate the need for Grid in due time. For now, one option is to do as you suggest, turn off the autogroup option in nUI and use Grid. There is a plugin you can use to put grid in your info panel, as well.
nUI will show you when a player needs a dispel, cleanse, etc, however.
I might suggest you try this for fun... turn off everything except nUI and Clique and run a few random dungeons and figure out what you're "missing" -- then you can add back the "missing" bits with other addons.
I always strongly recommend folks start with a clean install as per:
http://www.wowinterface.com/forums/s...ad.php?t=21716 and then go from there.