I don't think it matters much on the lower end (less than $1k range) with a pencil barrel. You may not even notice any difference accuracy wise. It's cleaner, but not "clean". In my experience the only way you get a sub MOA AR off the rack it to get extremely lucky. Even then it's not going to stay that way after several thousand rounds go down it (especially if you don't ONLY slow fire).
Once you get to about the $3k range, precision AR rifles with heavy barrels, my experience is that DI clearly holds tighter groups... without question. My high end rifles are shot even slower than my comp guns. Heat kills.
Like Wulf said there are myriad opinions, but there's mine!