Just got back from a stay at Mohegan Sun this weekend and really enjoyed the hotel and overall experience. The rooms are very well done, with quality finishes and attention to detail. The overall ambiance was light and open and the hallways smelled very fresh. This is a nice contrast to some of the hotels I've stayed in in Atlantic City. I was also impressed with the quality of service at the hotel.
There were a wide variety of restaurants and we were able to have dinner at Tuscany and a quick lunch at Bobby's burgers. All of the restaurants were outsourced and include wide variety: Bobby Flay, Micheal Jordan, Johnny Rockets, Geno's Steaks, Starbucks, Dunkin' Donuts, etc.
My only complaint was that it was difficult to make a table / bottle service reservation at the nightclub. The conceirge would not assist and the best we could do was leave a message on the number listed outside of the (closed) venu. It all worked out in the end, so I'd consider this a minor nit.