Looks to bend better but am really not seeing anything that can't be done with v3.  Of course the forums are covered in ooo's and ahhh's but there are already characters in RMP and Daz for V3 that look just like them. 
I don't think many will have a choice if they want new characters and clothes because once she is out, that is what Daz will push. This is the same thing that happened with V2, either learn to make your own or buy V4.  I bet Daz drops support for V3 almost immediately.