Rumors are saying there's no MMS next year anymore. This because no new date and location were mentioned during MMS 2013. Still there were 5,200 attendees this year, and it was almost sold out. I hope it will be continued next year, because MMS is the best event for System Center geeks! Let's wait for an official statement first.
This year MMS would be taking place in June in New Orleans. Then TechEd America is scheduled also. Because of community reasons Microsoft decided to split-up both events again, and schedule MMS for Las Vegas. For community reasons Las Vegas is still the place to be! For me it can be any place, as long there is space enough for networking and community! We'll see :-)