I to am pretty excited about the opportunity to mine for Bitcoin's, and from what I can tell you can have a decent ROI if you are patient. I also placed an order from BFL, and even though they are back ordered, I really haven't seen anyone else stand out as a leader in rigs. I did see KNC and then yesterday I noticed on CoinDesk a new company called Krater opened...
Any who... would be fun to build one myself as well
I really think KNC will be a leading figure in the mining race once they start shipping. They went directly to 28nm chips, while Butterfly is using 65nm chips.