So you're pulling ~660 per card for right under 2GH ? Nice.
I would do that if I had the kind of money to drop on 6990s... unfortunately I have to spread my 2GH over multiple miners

I only have about $1750 invested of which 1000 is already paid for over my first 3 weeks and resale value of all hardware puts me in the green 3-4 weeks in.
Yup - right around 1980 MHPS with 3 6990's, and 2 more on the way!

I'm considering this to be a geek investment. I enjoy overclocking and building high performance computers, so I figured why not. If the market ever were to crash, I'm always able to resell the graphic cars on eBay etc. Though if I invested money in buying in actual BTC, then I'd be screwed. (and they would be worthless)
My one rule is to NEVER buy BTC - only buy hardware to mine BTC.