Update as of last night, Sunday 9/17. I stayed at Nomad at Park MGM.
The slot machines work as far as taking your money and game play. There is no TITO working so if you want to cash out even say 75 cents it requires an attendant to come pay you out and it can be a wait. It was common to walk past 10 empty slot machines and see 5 of them with active credits below the minimum bet as nobody wanted to wait for small amounts.
Comps:
Resort Credit- Is only good at the location you're staying. We stayed at Park MGM so could only use it there. Our hotel check in, incorrectly told us we could use them at other mgm properties if we turned in the receipts. Not the case.
Free Play: Not working. You wont be able to use any freeplay. Players cards arent working at all and you wont be earning any comps as it cant track your play.
Wait times to check in can be long depending on where you stay.
MGM Grand has 7000 rooms so expect a wait. Nomad has 200 rooms so no waiting.
We could only get a single key for our room and they couldnt make a second one. Elevators are working but you dont need a key to access them or choose your floor.
Cosmopolitan was unaffected and was where we mostly played. Also spent some time at Resorts World. It's a really nice property.
Recommendations:
Easys at Aria. Incredible drinks and live music. It's a speakeasy behind the donut shop where the buffet used to be.
Bavettes Steakhouse- The chicago style ribeye with peppercorn crust and bonemarrow based butter is insane.
Have fun!