i used poser 4 or 5 way back in 2005 but moved to Daz in 2008 and i do prefer Daz but hate that i cant use poser dynamic clothing (dont have poser any more) and i've heard i'd need it if i want to import the clothing.

overall Daz seems cheaper (free adition and discounts help) and just if not more user friendly (although i miss poser lights too)

atm I use DS 3A which i got free with a magazine called DigitalArts (October issue) :) (makes DS4A about 70$ with Platimium discount)