I just returned from a 7-day cruise on the Magic with my husband (we're both around 30), his parents (mid-50s) and youngest brother (7). We had two cabins, theirs was an aft balcony cabin; ours was one of the deluxe oceanviews on Deck 1.
I'll try to sum this up without rambling too much. Basically, it was fantastic. The new ship is great and after our previous cruise on the Victory in 2008, we thought that the Magic really improved on some of the space-flow issues.
We stayed at the Sheraton Four Points in Galveston the night before, they do not offer a shuttle but were happy to provide a cab. It was a quick 10-minute or so ride to the port.
Plenty of closet space, having the extra bathroom was great, roomy enough for two. Some noise from the thrusters when we were coming into port.