My best friend's pre-and-post wedding party were in the lounge/club here and the reception was in the restaurant, it is one of the best kept secrets in Mandalay Bay!
Our waitress never kept us without a drink in our hand, she took pictures for us and even watched our bags while we danced. The atmosphere is amazing, not just because of the view but the design, the people who are there and the staff.
For the wedding we had one of the best three course meals I've ever had, we shared a selection of wine and mixed drinks that were always available when desired. Soft music, candle-light and a perfect view of the strip made this one of the most memorable nights I've had in Vegas. And the wedding cake/desert coffee were so good they had all the guests asking how to make them or where the ingredients came from.
The bathroom was super clean, with an even better view than the restaurant. The dance floor was perfect, good music and energetic customers. The bouncer even made sure the elevator rides at the end of the night weren't a huge dash to fit 100 people in 1 elevator.
There is nothing bad to say about THEmix, this should be the start to every good night in Las Vegas.