I belive sr101 is a better steel for edge retention but the dmdc is full flat ground and the ratmandu is not. is the ratmandu 3/16 or 1/4?
The RMD looks to be 3/16" to my semi-calibrated eyeball, definitely thinner than the DMDC. Its a good cutter no doubt.
My RatManDus measure .188" at the spine for almost the entire length. .188" = 3/16". I have owned a LOT of knives in my life time, but I've gotta say that the RatManDu feels better in the hand than just about all of them. A truly excellent knife!
As for the next size down I'll throw in a vote for the Rat Hunter. I have yet to be lucky enough to own one of them, but I have handled one and absolutely fell in love with it.