Upon check in, I was informed there would be a $25/day charge for extras that entitled me to 2 bottles of water, faster internet, bike rentals, and permission to sit on the AC beach chairs. That mandatory extra charge was not mentioned in advance, and the only amenity I used was the internet access.
I stayed at the AC Hotel Miami Beach for work sessions using their conference room. The room was right next to a high traffic area and was frequently quite noisy as there was no sound insulation. Do not use this facility for a meeting space. It's not built for it.
The rooms were adequate. My beach view room was made less spectacular by the dirty streaks on my windows, but I could indeed see the ocean. The floors were bare with no rugs, and the laminate flooring was marred and loose in spots.
Saving graces: walking distance to a number of restaurants/bars; fairly direct beach access (across the street, past other properties); mostly friendly staff.
Hard passes: breakfast - just walk out the door and grab something at Shepherd or Crema instead; meeting facilities - no privacy and meeting spaces are too close to the lobby.