gottasmile I haven't heard good things about MSC personally.
We went on an RCI cruise around the med last year and we all loved it. DC 11 & 8 are desperate to go on one again so we are waiting to book one for summer 2014 later this month. Either with RCI or NCL.
We were a bit worried about DS falling in, but he never even looked over the side once, let alone thought about climbing over. He was too focussed on what was happening on the ship tbh.
For us we felt it gave everyone the holiday they wanted. DH & I had time to wander around the ports, have a coffee and soak up the forrin atmosphere. And we didn't lift a finger the whole time as the cabin boy tidied our cabin and made our beds and someone else did the cooking. There was plenty of time for relaxing and I felt properly pampered and relaxed when we got back.
DD(11) came ashore with us when she fancied it, but stayed on the ship when she didn't and enjoyed the freedom of choosing what she wanted to eat and when. She says the best thing about the holiday was being able to do what she wanted.
DS(8) stayed on the ship the whole time as he was having too much fun in the kids club and wasn't interested in the ports. Once he went to lunch with them even though we were back on board. He loved trying new foods in the dining room as he could always order something else if he didn't like it. And he enjoyed the unlimited free frozen yoghurt.
We had an outside 4-berth cabin with the bunks above us and we thought it was fine for what we needed it for. It was nice to go back before dinner and relax on the bed with the sun coming in the window. And looking out first thing to see where you were. We didn't find it too small.