MEE balanced cables you say? I used to have one for 846 as well. Pretty neat cables. Since nowadays I mostly pair these with Micro iDSD BL I reterminated a 1/8 inch cable to a 1/4 jack so I don't have to use any adapters. One thing I like about 846 is that they're not source sensitive at all, you took the words right out of my mouth =D There is a noticeable improvement going from an iPhone to iDSD, these things scale pretty well. For kek and giggles I even plugged these into a friend's Ragnarock for once and boy that amp makes 846 sounds like its worth another grand. Still, with an iPhone you can get about 90% worth of its capability, not many BAs do that.
Also, hearing your statement about MD+ really puts my mind at ease. The impedance match thing reminds me of IM04. I don't even know its possible before I bought these but man, these things are hiss-sensitive and inefficient at the same time. On a low-powered source they sound very anemic while on a high-powered one hiss can drown out everything. You really have to take a close look at the output impedance before plugging these in. What's worse, these things only shine with desktop amps cuz no portable amps have enough juice for them. For this alone I reterminated the plug to a 1/4 one as well. If MD+ has the same issue I think I'm gonna pass, especially your statement about its bass. The only reason I'm looking forward to it is its bass, if bass on it is bloated and doesn't extend as deep as 846 then that's another pass for me.
In the end, I do feel like you pay extra for 846 just for its convenience and ease of pairing. These really aren't picky at all and the bass for BA is just phenomenal. Just asking, what tips do you use with the 846? I used to like Comply tips for comfort but they muffle the sound too much, nowadays I switched to westone star tips the sound is a lot less muffled and congested, but I do miss Comply for its BIG, THICC bass. If somehow there's a tip out there that finds a balance between these two it'd be great.