I've never had any problems with Poser 5. I did decide not to bother learning about Dynamic Hair, Clothing, the setup & the Face Room. Once that decision was made, Poser 5 was not so intimidating. I've temporarily shelved the Firefly renderer till I either understand it or get a more powerful computer (that won't happen in the near future.)

One great thing about Poser 5 is that it can use jpg bump maps. I recently installed something into Poser 4, and spent a great deal of time converting the bump maps to BUM format. That is a total pain in the ass. Yes, I keep Poser 4 around for some things that still tend to make my puny computer choke in Poser 5.

But Poser 5 is my main Poser app.