Okay, so I'll take the unpopular approach and vote in favor of Dat.
His stuff may seem repetitive, but he also had to perform his material for the NBC audience like 5 times in what-- three months, maybe less? I can understand needing to repeat bits that work well. Maybe the veterans could have still-relevant and fresh stuff after performing for the same people five times in a short period, but not many of them seemed to deliver the goods.
Dat definitely has his schtick (which I think he varies effectively at times), but having a schtick isn't uncommon in the world of stand up comedy.
The other thing I like about Dat is that he doesn't repeat OTHER comics.
Some people have pointed out that Rich's stuff last night was stuff they've heard other comics do better, and I think the same goes for Tess (definitely) and even for Ralphie's set last night.
I've seen Ralphie be original, but come on... how EASY IS IT to rant about wanting cheaper gas???? Especially for 5 whole minutes! Excruciating!
BTW, I also can't believe they're making us wait a week + 2 ridiculous hours to find out the results. After the disappointment that was last night, will we still care?