exactly why I moved on from them.....simply not enough density possible.
I am with you. It shows there is no perfect GPU they all have advantages and disadvantages. I don't regret going with 5970s. Highest MH/W and awesome density. I couldn't imagine running a 15 GH/s farm using 5830s. Thats what 50 GPUs?
Still everyone's needs are different. If someone is a gamer who wants to mine part-time I would say get a 7970 (or two). Cooler and quieter than 5970 but I wouldn't want to try and build a farm out of them.
i look at them as very nice 'training' gpu's for those (like me) that are getting started with mining. they can be obtained easily, and with a bit of a warranty for short money and aren't really all that bad on power when tweaked for mining. for example, i wanted to test all sorts of things regarding setting up a 'big rig' and certainly wasn't going to run out and drop almost $3k on 5 7970's while not knowing what i'm doing. but for ~$500 in gpu's one can learn everything it takes to build out a large gpu rig including space, power, cooling, adapters, os/software management,.... - without being overly paranoid about damaging something.