I haven't had any experience with the 480s, but I will say it seems there was a lot more "work" to get the 570s and 580s working as well as people say the 4 series work.  That being said, as irritating as it was and with the 2 days I lost tweaking, I would probably buy the 5 series again because it provided a good learning experience and in the end I ultimately got the same results.  If you're in a rush to get started, the 4 series might be better, but if you want to learn more about getting your cards to optimal operation and understanding why people are recommending what they do, the 5 series may provide that with the learning it takes to get them running right.