Honestly very close.
The Duelunds have a very organic bottom end in full range production, the MR is very tight and powerful. It will come down to system synergy. No doubt if your more into tube sounding bass that the duelund will be more like that, the MR is a little more highlighted.
Tuff call, however I do ultimately in a speaker application use a MR but then again in a woofer its a parallel cap, and for output caps I do prefer the Duelunds vs. the MR in some ways. So it will be very difficult to say which is totally better for all applications, however for straight out cost effective I can tell you the MR is right there overall. You have to spend A LOT more to do the duelunds.