I had been using a profire 2626 for the past 12 years or so. I switched to the Behringer UMC1820 because it plays a little nicer with Linux.
The Behringer seems to have more low-mids in the output than the Profire 2626 did. It's a little off-putting to my ears. I was very accustomed to the old sound. I'm hesitant to call the Behringer muddy in comparison, but it might be.
I have an old DAW system using Win7, Sonar Cakewalk 8.5 and a M-Audio 2626 (firewire).
I plan to retire my old hardware and move to a newer system with Win10, newest Cakewalk (while it still runs), also migrate to a new DAW over time (maybe Cubase). The new system will most likely NOT have Firewire, so I'll need a new audio interface.
Picked up an M-Audio axiom 88 yesterday and I'm in love with it. The hammer actions keys feel amazing. They are so close to the feel of my actual piano. The pads aren't amazing but they do what you need them too. But the biggest perk is being able to control your daw with the faders and knobs on the Axiom, it really had helped with work flow.
I've had an M-Audio Delta 66 w/ Omni IO breakout box for around 10 years.
The Omni IO went crap, a couple weeks ago, and I just replaced it with a Focusrite Saffire Pro 14.
I did some recording (AudioTechnica AT4033SE), on the new Saffire, and I had to crank the pre-amp up a lot higher than I did on the Omni.
I have a pair of M-Audio Studiophile BX8 monitors (NOT BX8a) that the Tweeters don't work no more. I talk to the parts service of M-Audio and they don't have that part availeble anymore. They send me a list of there oficial service centers to see if by any chance you still got that part in your stock but they dont. So now I have to find a replacement for it.