I'm the guy in the video proclaiming the Uptown's greatness, and I'd like to clarify what I mean on Head-Fi as the audience I reach on YouTube is much more broad and not as knowledgeable. These are not the best headphones under $200. When compared against the DT770 PRO amongst others, the Uptown are put to shame; however, 99.9% of my audience doesn't have the proper equipment to power a less efficient headphone. Nearly all of them are playing their music through their iPhones and iPods with the occasional cheap headphone amp like the FiiO E7. Because of this, I posted such a positive review because I genuinely do feel that they supersede the M50 when in casual use.
Now, I will not claim know everything about audio, but I do have a decent amount of knowledge, and have been purchasing nice equipment for years. I own a Woo WA6, HD 650, D5000 Markl Mod, DT990 600 ohm, HiFiMAN HE-300, etc. Nonetheless, here's what I think of the Uptown:
First off, the low end is not so dominant which is what I always felt to be a drawback on the M50. Conversely, the high-end is very nice and clear, but not overpowering either. The mids are where these headphones really can show up the M50. I always felt that the bass on the M50 bled into the otherwise unremarkable midsection; however, the Uptown have really warm and exaggerated mids. This makes listening to classic rock guitar solos amazing. Not to mention the fact that female vocals sound lush and concise. I won't try to pretend that the Uptown are accurate, because I don't believe that they are. They are very warm and buttery and smooth which I feel makes for a fun listening experience, but not an analytical one like many competition. Soundstage is surprisingly good (something I found to be less than remarkable in the M50), especially for an inexpensive closed-back can. Imaging is nice but nothing out of this world. The Uptown are starkingly efficient (even more so than the M50) and actually don't respond well to amplification which I consider a drawback. The sound does open up and improve when plugged into my Epiphany EHP-O2 or my WA6, but there is a noticeable hiss. Again, though, for most of my viewers, they're not amplifing their source, so the Uptown are more well suited for them.
Again, my audience is not an audiophile audience. They're mostly low-level consumers just beginning to enter the higher audio quality market, and I feel like the Uptown's sound would be more fitting for more people in more genres on more playback devices. Not to mention the build quality and comfort of the M50 is surpassed by the Uptown (other than that stupid spaghetti cable).