Hmm, I might be receiving a 8 GH/s at first, but I want to get a 50 - 60 GH/s one. I have it on preorder. But I have the 8 GH/s one shipping to me now.
Definitely use a pool with 8GH/s. For the 50GH/s you would mine an average of one block a month. Up to you whether you take that risk, but also beware orphaned blocks. I'm watching this thread for a reply to a question about configuration needed to reduce orphans
https://bitcointalk.org/index.php?topic=238089.0