I'm definitely going to be looking for a lightly used MM-100 once the hype dies down a bit and they start hitting the classifieds. I haven't heard the HD569 but I have the HD560S and they are just fantastic. I use them for just about everything else other than critical listening but I agree on the form factor. Great for movies as they just disappear on my head for a few hours and soundstage better than my other Senns except for the HD800S.i'm really excited to try the new MM-100, can't beat the price. i also thought about the 1000k but hifiman qc just bothers me. i just deleted my raging paragraph as to why and will just say they're just not for me anymore
you know what the surprise of year has been for me? the lowly Sennheiser HD569. I got them at black friday last year and have been constantly impressed with them. they're not great from a technical perspective. but man are they overall just fun and agreeable to listen to. light on the head and easy to power. they like tubes, and just about anything you plug them into. color me impressed!
I know I'm just going to have to suck it up in the near future and buy a Susvara at some point but it won't be this year. Thanks for the feedback!