I think V3 & V4 compliment each other very well. I'm afraid I really haven't used V4 very much as I just love the morphs which come with V3. My latest render uses an old V3 character of mine, I think she would be hard to reproduce with V4. I think I could do it, but it would be harder without the extra face morphs that V3 has. Mind you, there's always the morphing tool.