Both of those boards support virtualization, but whether or not you will be able to create virtual machines depends on the CPU you use. Not all the CPUs you can use in these boards support virtualization. In general, any of the processors that are of the 'K' type do not support virtualization. You will need to check the CPU specs to see if virtualization is supported or not.
Which board is better? That depends on your own needs. In general, I would choose the B75 board, since it will work easily with both Sandy Bridge and Ivy Bridge processors, has more SATA ports, and more video outputs.