I couldn't care less about what they think.
The DT770: Sure, its good in the studio for professional use with its perfect build quality and long cable, but it's sound is flawed. To me, the main problems are the bass tightness, and sucked out mids. These aren't very engaging headphones imo, so they seem kind of cold and dry next to something like the M100 or WS99.
The WS99: Isn't without its flaws. They are a little uncomfortable, since the pads are really thin, but they are NOT built bad. Audio Technica is Japanese, not Chinese, and even China, who owns Fiio I believe, makes some nicely built products. Anyway, they look nice, feel nice, and are very convenient. Sound wise, of course everything is controversial, but the WS99 has the perfect amount of excitement and intimacy with its upfront lower mids and mid bass. The highs are recessed (which I am not a fan of but apparently tons of people are), but not too recessed like the UE6000 per say. The mids are extremely clear, and the bass is probably the best I've heard.
The M100 is a ws99 with slightly better build, looser yet deeper bass, more highs, and more laid back.
I'd also recommend the Focal Spirit One.