I've stayed at the Allstar Music 3 times, and I really like the resort. The rooms were just refurbished within the last year or so, the food court has some pretty good eating options, and I thought that the bus system was pretty good. My only complaint was that in the evenings some of the parks did not have separate bus stops for each of the Allstar Resorts and leaving the AK and MGM (now DHS) was pretty chaotic.
There are activities by the pool for the kids and at night they were showing a movie by the pool.
All in all it is a good resort for the money.