My family of 4 will be staying at the Vistana Villages in October. After staying at the ASMo in January, DH said if we went back he would not stay in one room again. My kids are small (4 and 1) but it was still cramped quarters. The kids, however LOVED ASMo. We had a room on the first floor in the Toy Story courtyard (it did get a bit noisy at night). The one thing I miss the most when I do not stay on property is the bus transportation.
I was able to rent a 2BR at V V for $700/week from a timeshare owner. This was a great deal that I couldn't pass up (no taxes or any other type of misc. charges). The place just opened last year and I have read nothing but great reviews. I believe HIFS is closer to the parks than V V, but V V is not much further away.
Hope this helps, and have a great time no matter where you stay!