The sound signature was just too dark for me. I kept a/b'ing between my TMA-1's and M50's. I liked the mids better on the TMA's since the M50's mids are a bit recessed. Like you, I'd like a bit more in the sub-bass, but despite what other head-fiers were saying, I thought the M50's had better bass extension. The TMA's had more bass everywhere else except for the sub-bass. But ultimately the highs are what killed it for me. I was looking forward to a darker headphone since I'm very sensitive to treble. I also found my M50's to be fatiguing sometimes. But the darkness of the TMA's was too much. Although I did like the mids, the treble attenuation muffled up any vocals. Also, the TMA's are very comfortable, but with glasses, My ears started to hurt before the one-hour mark.
So IMO M50 vs. TMA-1:
Lows: M50
Mids:TMA-1
Highs:M50
Comfort:M50
Portability:TMA-1
I got my M50's for $110, and I just couldn't justify spending almost twice as much for an inferior sounding headphone. It's well built, has a great design, and is very portable. That much appealed to me a lot, but as far as sound goes, not worth the price.
Currently, I listen to my M50's with DT250 velor pads. This fixed the sometimes-piercing highs for me and increased the bass slightly, just to give you an idea of another route to audio happiness.
As for the D1100's they have more bass, better mids, and slightly rolled off treble compared to the M50's. But I think the M50's have tighter and deeper bass. This is from memory. My friend had a pair and I listened to them briefly. Also, they were very comfortable. Very light on the head.
There you go. Sorry for the long post, but I hope it helps!