Hello...maybe i can offer some insights.
I consider All Star Music my *apartment* when i am at WDW. I have stayed there almost every time i have visited WDW and love it. Basic and clean, simple yet fun...it fits like a glove for me. I spend all of my time in the Parks when i am visiting WDW so i do not feel a need to stay at any of the fancier places. All Star Music rocks.
So why is it my first choice..and a favorite you may ask?
Well for me, there are several reasons. These i have noticed from observation, and others from experience where i learned a few beneficial tricks.
First, i like it because it is almost always the least expensive choice when it comes to Disney Resorts. It may be one of the oldest Values but i like the theming. All i really need is a bed and a shower...and this fits perfectly for me.
The other reason i like it is that of all the Values, it is usually the least crowded. Most families tend to choose Movies or Sports over Music, mainly for the theme. Also, as noted by Disney themselves in various travel guides, the concentration of families with kids, and kids in general, is much lower at Music when compared to Sports and Movies. Again, that is primarily because most families with kids would rather stay at a hotel with Toy Story and Dalmations themes then generic music icons. All Star Sports tends to get fllled up with tour groups, visting high school bands/sports teams, and other large groups throughout the school year. So Movies draws the kiddies and young parents, and Sport tends to draw the jocks and highschoolers.
Many Guests prefer staying at the newer Value Resorts like Pop Century, but the size and bus situation there turns me off...plus, you are literally out in the middle of nowhere in my opinion. It is just not attractive to me...but i know it has a loyal following.
Another big advantage i see in staying at the All Star Resorts is that you have more bus options during Park Close. When a Park closes, and everyone rushes out in masses to stand in huge lines waiting to board a bus back to your Resort..you know the scene. After a full day at the Park..you are pooped...and anxious to get back to your hotel and crash for the night. If you stay at any other Value, your option is to wait in line for ONE bus at a time. With the All Stars, you have THREE options in many cases. All three All Star Resorts are connected together via a parking lot...so you can take any bus to Sports or Movies and walk a couple of minutes to Music. This stragety has saved me many times from standing forever in bus lines post-Park close. Hop the first one that arrives and just walk it. Try doing that at Pop or Art of A....ha! Of course...things may have changed now...this only works if all three All Stars have seperate buses, which in the past i have seen during Park Close. Take it with a grain of salt...but it is worth mentioning.
The only downside i see staying at All Star Music is the food court. It needs to be freshened up a little decor-wise. When i do need to grab a meal at my hotel, i now just walk over to Movies as i love their themed food court. Well worth the walk...and they serve the same menu, just with a more appealing visual zing.
Hope this helps!
Have a fantastic visit!