There is already a thread on it here:
https://bitcointalk.org/index.php?topic=277901.0

The problem isn't what they promise. The problem is when will you get what you were promised.
Last summer, BFL made a promise to deliver hashing hardware in the fall that sounded like an amazing deal. They still haven't delivered that hardware over a year later.
You would be wise to pick a company that can actually deliver product without year long delays.