Things I hated about the Signature:
1) This hotel is so far from everything!
2) You can only valet! Blarg!
3) If you book through a third party, you can't call the concierge/maid service directly. You have to call the third party directly.
Things I liked about the Signature:
Everything else!
The rooms here are actually very nice and because the property is away from the Strip, it feels like you're in a nice apartment complex or something. We got a cheap rate through a third party, so for the price, I really liked our room, especially since it had a kitchenette, which makes eating and pre-partying a lot easier.
If I could get a cheap rate again, I'd stay at the Signature, but this time I'd book directly with MGM instead of going through a third party.