Our favorite board of the bunch for extreme benchmarking is the EVGA E657. In terms of ease of use and 'overclockability' this board wins on all counts.
Heavy load benchmarking stability is this board’s strength and at its price point there is no other P55 board that delivers on as many levels for the overclocking professional. EVGA is using TCYO AMP and LOTES sockets exclusively for all their P55 boards at this point