Just back from MO... Some quick thoughts:
I got an upgrade from a booked Exec Suite to a Dynasty Suite. I was *this* close to canceling the whole reservation due to various online images of the Exec (it looked entirely too smallish for me), but stuck with it and made a backup res at Encore just in case. I'm elated the Virtuoso upgrade pushed through, as I don't think I would have enjoyed my time in the Exec, especially knowing how variant it seems the floor plans are. MO needs to be more clear on their website about that issue.
All turned out well. MO's level of service is, as already said, impeccable. Last name greetings around every corner and an effortless flow of help that seemed to come from thin air and disappear just as quickly. I never felt hovered over. Everything was just right. Very impressive.
I requested Bvlgari Green Tea products in my room, as I'm not a fan of the white. No problem. They also pre-stocked my minibar with specific beverages that I wanted while I was there. Also, no prob. Great pre-arrival concierge staff.
I'll post up some pics on my blog in the next week, but rest assured that I can add my praise to the already heaping bowl. While I found the rest of City Center to be somewhat trenchant, MO is the saving grace: A peaceful, elegant getaway from the bain of MGM service standard and environment.
BN