Hi-
I have a DMM-60 mower and I absolutely love it.
It replaced my 42" side discharge deck on Toro classic 315 tractor.
I think the DMM does a better job.
The only thing I have to be careful of is scalping. I like my grass long as we get hot dry summers that burn short cut grass here in new england, so I keep it high, but even still w/ the extra wide deck, I have to be a little careful of scalping in spots where it's somewhat uneven. (I have some ruts from the day we had a bandit model 250
chipper in the yard -- story for another time)
If your yard is major uneven, then you will need to be careful.
Otherwise I like my deck -- I can cut at full forward speed in low range with ease. I may have to back off the hydro pedal a little when going up a steeper hill as the deck is 400 lbs, tractor 2000+ lbs, I'm another 275 lbs -- lot of weight!
If I can find some pictures of finished but w/ CK-20 and DMM-60 I'll post them. I don't think I have any. If it's still useful to you in a month I'll probably be close to my first cut of the season. I plan to buy a spare set of blades and sharpen the ones on the deck now and sharpen often during what will be my first full cutting season w/ the CK-20.