I've now stayed here and down the road at the Mohegan Sun. (Never stayed at the 'original' Foxwoods or any of the other properties.) MGM rooms were roughly equivalent to Mohegan Sun, and more expensive. Where they win out, however, was the hotel seems better run. For instance, we had a reservation for 3 rooms and they were easily able to give us 3 rooms right next to each other. Had an ordeal down the road a few months back trying to achieve the identical thing. Maybe it was a slow week-end, who knows...?
Crowd here was also somewhat more well-heeled than down the road (which actually made the casino LESS fun IMHO.) Dining choices are OK, but also more limited here. There are 3 steakhouses on the property, but not ONE seafood place. They must realize this, and it's something they should fix.
The biggest drawback is one of the rooms reeked badly of smoke. The other 2 were fine. (I thought they had great sprays/technologies to deodorize rooms these days...definitely not the case here...)
Is it worth the premium price? Probably only if you plan on getting drunk (which is a valid enough reason.) Otherwise there are plenty of good options (national chains, etc.) 10-15 minutes away.