Were you using the M/M stack in your profile for all of these comparisons?

A good question. Answer: not always. For the DT1350 and Grado and Momentums, yes. Not the AKGs: those were with an E17.

Brilliant poem! I'm also looking to check out some Mad dogs this new years...

Awesome poem!! I really enjoyed it. Currently saving up for a pair of MD's to compliment my VSonic GR07's

It's a good headphone to go with. Like I've said in some other threads, I have nothing but love and respect for these, but lately they haven't been connecting with me, perhaps due to my new glasses, perhaps due to the weight - I don't know. I'm a picky dude. I still can't recommend them highly enough - they are truly amazing, and Dan is a very smart, very nice guy.
 
I think perhaps some of my discontent with them is that I'm realizing that I gravitate more towards an exaggerated, "fun" sound more than accurate, and maybe something that sounds more vintage-y, and less crisp - not that these are sharp or hard to listen to. I think I'm just a tired teacher lately, and want to come home to some stupid headphones, not smart ones like these? Not sure.

Just added an epilogue to the poem (the first post). To make a long story short: the Mad Dogs just weren't doing it for me for my extremely big head. Amazing headphones, very well done, but just didn't press my buttons. I got a Sennheiser HD598 for the classical and softer stuff, and yes, went right back to the K550s. They may be flawed, but they work for me. Simple, accurate, and somehow (for me) the most comfortable headphones I've ever tried.

You've totally got that right- the MD vs K550, you echo my sentiments exactly! I'm returning K550s and keeping my mad dogs, although I think I will miss them a bit.  The picky seal alone has killed them for me. Mad Dogs I put on for first time & are instantly comfy- much more so than fiddle K550s

Well, after all this time and shifting around of equipment and whatnot, I've come back to the Mad Dog. I added an epilogue. It really amounts to this: I don't want a headphone that's too shrill, and I demand something that is made well. These are the best-made headphones I've ever seen, period, and they have a rich, lovely sound. Now that I have a kid on the way, I can't afford to buy any more for a few years, so this is seriously it.

Let this be a lesson to anyone: do not turn your back on good quality. There's always grass on the other side of the fence, but once you've found something that is solid, sounds great, and is made with love, stick with it. Just my two cents.