Thats a very good deal on that oneJust a heads up to any one looking. There is a icx6650-56-e-adv on ebay right now. The seller countered with $300.
Debated on picking it up... but I grabbed an sx6036 for my 40gbe needs...
Just a note - on least on my 6650, it is quite loud, and the fans spin up about every minute (it is very cool so I think that might just be how they work). I've swapped the fans and power supplies and it still operates the same.
It's buttcrunching powerful, but very noisy. Less so at idle, but when it spins up quite noisy. Idle isn't exactly a walk in the park. Much louder than my 6610s. Definately not something you would want in the same room you are in - I can hear it through my basement walls a little bit.
With that said it's pretty much an end-game switch (at least for me) power/connectivity wise for 10/40g.