I received my MT220's yesterday, and while I've only had a short time to listen to them straight from an iPhone they are very promising. Comparing them to the Sony 7520s from my iPhone the MT220s are less peaky in the treble while maintaining excellent detail. The bass on the MT220s also appears to be a bit tighter, less boomy than the 7520s. I still hold the 7520s in very high regard, but the MT220s may have just surpassed them.
I will do some more comparisons on my main rig (ODAC - Burson Soloist) later and will probably compare them to my favorite closed headphone so far, the HP100.
Oh, that is definitely a comparison I am looking forward to! I am delighted with the MT220 (it is now my reference headphone) a great accompaniment to the HD 650. Also, what blows my mind is the performance it is capable of without an amp! I tried the Microstreamer, Burson HA160 & the O2 - all they did was add a little "polish" to the already impressive performance
As you can see already, I preferred (barely) the HP100 to the MT220 and both of those to the 7520. What I can tell you is that the HP100 and MT220 are so close that it was almost hard to pick a winner. The main differences between the two are the slightly more treble air and bigger soundstage of the HP100.
Of course, one could argue that the MT220 is better since it has a smoother treble, meatier sound and more intimate soundstage. It's all down to preference really. I prefer the HP100's presentation (treble detail, soundstage and slightly tighter bass) but the MT220 is very good as well.
I'm torn honestly, I can easily recommend both headphones to someone looking for a closed can in this price range. I will also say that the MT220 is easier to drive than the HP100. The MT220 play fine from my iOS devices where the HP100 really needs a little amping to shine.
The 7520 was kind of like the odd man out here. To me, the real race was between the HP100 and MT220. The 7520 was a bit edgy in the mids and there was occasional harshness in the treble. It also sounded a bit metallic compared to the other two and to my ears had a sort of reverb-like soundstage thing going on. The 7520 had more bass than the other two, but to me, it seemed like more mid-bass where the HP100 and MT220 had deeper, tighter sub bass (which I love). I'm not saying the 7520 is worse than the other two, but to my ears, I definitely preferred the HP100 and MT220.
I actually compared the MT220 to my Philips X1 just for giggles and was surprised. Just a quick comparison, but to me, the MT220 sounds like a closed X1. Similar sound signatures, warmer, great bass while still maintaining excellent detail retrieval.