Based on the price, best choice would be Z97X SOC, or Z97X Gaming 5 if prices are to be ignored. Well all 3 are great OCing boards with good enough hardware but Z97X Gaming 5 isn't really worth extra $15 over SOC.
Z97X Gaming 5 has double the number of true phases than SOC, so it may OC better. But again, the temperatures will bound you before actual hardware does. In real world, it won't affect the OCing potential or longevity of the board.
Z97X Gaming 5 has double the number of true phases than SOC, so it may OC better. But again, the temperatures will bound you before actual hardware does. In real world, it won't affect the OCing potential or longevity of the board.