Yes it was like 4 years of daily use, and basically my daily driver, had some issues with my Alessandro MS-2 (but later turned out it was only the jack). But when the Pro 900 no longer works without jiggling the headband to get sound, i just decided it is time to upgrade and 2 options either the DXP or Studio, went with the larger driver.
S-Logic well yeah, hehehe, lower SPL means larger sound stage i guess, Pro 900 sounded incredible at the time with my Meier 3-Move dac/amp combo, but damn, it is even better now with the Heresy and 3-Move or Ultrasone Nanos or Hizdis S8 and Zen Stack. Pro 900 sounds wider and surround to me, it was great for movies etc. If i can fix the Pro 900 then that would be awesome. (i failed to fix my Pro 750 with the left speaker failed after 7 month).
Bass wise, despite the DXP having a larger driver, the bass is pretty darn good, but with the comparison with Pro 900, i would say overall if the pads of Pro 900 can be fixed (bad comfort) the Bass is even better on the Pro 900, but the pads were bad, after 3 years of use it hurts my ears so i had it removed to some brainwavz angled pads.
Pro 900 i think has overall more detail with the old stock pads compared to the DXP with the Brainwavz.