With the massive amounts of money that are going into mining hardware right now, I wouldn't touch it with a 10-foot pole. If you do, BFL is the most profitable option by a wide margin.
Hard to believe the BTC community hasn't identified BFL's chips.
Open solutions are stuck at poor profitability due to not being able to identify, IMO, what is a commodity chip.
identified. It is a Stratix III EP3SL200 or EP3SE260: