Monte Carlo was nice, 15 years ago. I just recently stayed at Park MGM. Apparently they have a newly renovated tower with everything done up really well. My girlfriend didn't know this when she booked and we got a room that just had the minimum facelift from being Monte Carlo.
It was in July and the air conditioning didn't work, the room smelled, the strip view was non existent. We decided to check out the next morning and luckily Expedia gave a refund on the remaining 3 nights we had left.
The front desk didn't even blink an eye when we told them how gross the room was. I would never go back.