Having stayed in both, I strongly recommend the suites. The bathrooms are much bigger. You can shut off the toilet and tub from the sink area in the one with a tub. The microwave is a real plus.
My daughter and her friends, all around 22 years old, have slept on the Murphy bed and had no problems at all. I have always had the bedroom, and that bed is much better than the full beds in the standard rooms. We've had at least four different adults sleep on the sofa bed, and not one of them had a problem with it.
We had the exact opposite situation with the noise. The standard rooms were extremely noisy, especially at night. You may as well be in the room with people on top, bottom and both sides of you. It's particularly bad during the night when people around you go to the bathroom. I was constantly tired when we stayed in the Mermaid room. We have never had that problem in the suites.
If you want to go with two rooms, I recommend two adjoining rooms at Pop. They are new and way nicer and cleaner than the Mermaid rooms. It's very easy to walk over to AoA and visit. Pop has a great food court. There's also less walking. We usually stay in the 90's building.