If your son is interested in a service academy AND wants to participate in Band, I think USMMA is the best option. It's the only service academy with a student band. However, understand that Band is only an extracurricular - you don't go to Kings Point to be in the band, just as you don't go to KP to play football, or lacrosse, or track, or [fill in the blank]. At the end of the day, everyone who comes to KP studies to be a deck officer or an engine officer. Your future career is paramount, whether in the merchant marine or active duty. Everything else is extra, including Band. If son is looking at a music career, KP's not the place.
Our DS is in Band Company. When he applied, he knew he would be in Band Company - band showed up on his high school transcript. While he may not be crazy about all the band practices or all of its "quirks," he loves the people in Band Company. I asked him once whether he'd rather be in a different company and he was emphatic in saying "NO!" He's also on the track and cross country teams at KP - loves running and shares with his team a school record for a relay. At the end of the day, though, he's focused on where he's going to be after June 2013.