the MIST doesn't use a real 68K CPU but a soft-CPU in the fpga that leaves the door open for higher speeds and more varieties of CPUs as well.
At the moment it only supports ~8mhz 68000.
mikej's board can use either a soft cpu or a real 68060. The minimig can use a 28mhz 68000.
It's entirely possible that this will sit below the minimig in terms of performance, but above it in terms of ram.