Depends on which one, I didn't see the one you were talking about.
I know they were selling 480 Lightnings for that price for awhile.
If noise is a concern I wouldn't go with a reference blower card, they're all the same, loud.
If power is a concern I'd go 28nm.
A 480 would be considerably faster than 10-15% in some newer DX11 titles, like BF3, and Batman AC. If you are looking at a non reference card they'll typically overclock past 580 performance without much issue. Power though is going to be about 100 watts higher at stock vs a 5870, however those are old reviews. Newer ones show Nvidia was able to get some of the leakage under control and reduce the power draw fairly well. They also use less power the cooler they are, so a good non reference cooler would help mitigate some of the additional power.
If you can get a good price from a bit miner for your card I'd do it, and the card you're looking at is non reference it should tide you over until 28nm refreshes later this year.