The DSP version appears to offer some effects in the monitors during tracking, such as eq, compression and reverb. The website seems to indicate that the reverb would not be printed to the track (which is good) but is just for monitoring. I didn't get whether the other effects were meant to be part of the recorded track or just for monitoring. I would hope it's just for monitoring because they could be done better after tracking in most cases.
It also claims to be able to simulate monitoring on speakers for users who have to mix in headphones. That could either be really handy (but probably not a true replacement for speakers) or a disaster depending on how well it's implemented.