According to the stats on Butterfly Lab''s webpage, the BFL Mini Rig will be the most powerful miner in the industry, running at 1,500 GH/s. From what I know, there is nothing out there in the market at this time that will compete with that hashing ability.
As for power specs, I hear they are still working out some issues and the power specs have not been finalized yet. While I know that there are some people out there who are wary of BFL, I have ordered FPGA’s from them before with no problems and I have current orders with them for ASIC’s that I fully expect to be fulfilled due to my previous experience. Just have to be patient.