I ended up returning my pair of HP50's. Nevertheless, its sound was very clear and slightly warm. However, I ended up preferring the Momentum's midrange presentation. It seems to just nail it in terms of vocal tonality. Also, the bass quantity, though accurate, on the HP50 was simply lacking in drum and bass while the Momentum had just the right amount of boost to transition through different genres with no sense of bass deficiency. Soundstaging on the HP50 was marvelous and very spacious making the Momentum sound somewhat congested in direct comparison. It is until you listen to the Momentum more and readjust to it you realize that it's not congested sounding, but rather intimate, forward and warm sounding.
Ultimately, it boils down to preference between the two where the HP50 is a open, controlled and accurate sounding headphone while the momentum is a more laid back, rich and warm sounding headphone.
I had the same expereince as you had, I simply preferred the Momentum headphone over the HP50. :)
I didn't had the first expereince though, I ordered due to the rather hefty praise they had gotten online and I need to try more before jumping on that "order button" ;)
Edited by Foolwolf - 3/14/14 at 3:19am