Hey mate,
I've got one running in mine. You can check out a picture of it here:
https://www.reef2reef.com/threads/darkreefers-cade-reef-s2-1800.1010189/post-12837210
I used the 'refugium' spot to mount it, but I've been meaning to cut the baffle out and move it over to the left and then reinsert the baffle to make the refugium section a little smaller and eventually get it up and running.
I absolutely love the unit so far. Have had it for about 3 or 4 months now and nearing the end of my 2nd roll.
Changing the roll was so much easier than with the Clarisea I had previously. I've even been using the little media tray in it recently for some rowaphos/carbon.
The app is simple enough to use and informative and you can set it up to notify you when you're getting low, I set mine to ping me when there's approx 2 weeks left so that I have time to order a new one (though I usually keep a spare on hand).
I had a lot of issues with my SK-5000 Clarisea that I bought just so it would fit in that first sock section in the sump so I didn't have to modify anything but the Reefmat hasn't skipped a beat.
Personally I love rollers because I'm a little lazy and taking out filter socks when they build up is not fun and neither is having to wash them etc. I've had 2 rollers on this tank, and had a little drop in roller on my first tank and I haven't looked back on the roller game.