I prefer V3, but then I have no experience with V4 and very little with Aiko3.

From the gallery, it does seem to me, following comments above, that while V4's body generally bends better, I rarely see really beautiful V4 faces, and few people seem to be really using her body morphs much, so I can't compare her potential voluptuousness with V3. Doesn't mean V4 can't be pretty, or have a tweaked out bod -- I just don't see much of it. Maybe  she's just still relatively new. 

I do like the V4 portraits by Mark@poser above.

Vicki 3 has a great face but her shoulders bend weird and her thighs flatten out with kneeling poses.<

Yes, definite problems there, but I highly recommend these FREE morph corrections graciously provided by Maveris. They include morph targets for both the sides and tops of her shoulders, top of thighs, back of knees, and the inside of her forearms, plus an eye-control  injection that gives better results than either "point at camera" or "point at prop behind camera" or, at least usually for me, manually focusing the eyes.

http://www.digitalmeanderings.com/downloads/downloads_utility.htm

Gallery