I have stayed at both!!
One I would return to happily and the other I would never go back to again, even if they offered it to me for free!!
Vistana Villages is about 5 minutes from the main vistana (cut through past the Premium Outlets and then turn left onto I drive.. and its just there...)
As previously said, Vistana is much bigger.. and has more pools - although the pool at Villages is absolutely huge (plus there is a kiddies pool and an adult only pool) - The Vistana Villages pool is much bigger than any pool at Vistana.
There is an onsite deli/cafe type place where you can get hot food around the pool or take out to your room at the villages. It was fine.. nothing spectacular. I think at Vistana there is something similar although its inside.. with probably better food to be honest.
The apartments at Vistana are varying! From really nice, to absolutely awful... although the awful ones are quite big.
The apartments at Villages are smaller, but newer.. although the decor in ours in building 1, was quite old fashioned and fussy as bits of it have been up for 6 years now.. and we prefer a more modern, classic look. I didnt see in one of the newer blocks, but I suspect they were more to my taste.. However, they were well maintained, clean and had everything you could imagine. Vistana was dirty and looked like it had been decorated circa 1982 and not since. Plus, I got eaten alive by mosquitos at night.. (only two places this has happened to me, and I am extremely allergic to insect bites, so this is a major concern to me.. One is Vistana and the other is Summer Bay). We sprayed outselves in bug spray every night.. and the sheets and my Pj's but still I got bitten numerous times. Even my baby son was bitten.
The staff at Villages were helpful and knowledgable. The Staff when we were at Vistana were the worst I have ever encountered at any resort we have ever been to.