MHO on my experiences with all 4 VF100s:
For the first 3, they are all plain valks; no super or armor parts. I found them fun to pose and nice looking enough. Esepcially the VF-25S; the 25F face paintwork is sometimes bad, and the 25G eye piece looks too dull. 25S is the best one to me.
For the Armored 25F; it's a different game. Because of the design, the backpack is so heavy it can't stand on itself. Similar problems exist that it's now more a display piece than a fun toy as I experienced with the plain valks. It looks nice, it can do some nice poses with a good stand (the one that comes with the set is not good enough for battroid mode at all), but it's not something you can watch tv and play with (just like the 3 plain vf100s).
P.S. It's around US$48 to buy it locally, so it's not as difficult a decision to make for me.