For me, a guy who works with sound as a hobby, this is an expensive unit. This a point that is likely rendered mute for anybody who works with this stuff professionally or semi-professionally.
With that out of the way, I love this product. It is intuitive to use, has any and all input and output options I could ever need and every time I think "could I?", I can. I currently have it running as an effect processor and vocal recording chain while hooked up to my home studio, and as a live rig for vocals when taking it on the go.
I'm not the guy who will be able to give you the most detailed breakdown, or the professional's perspective but here would be some of my pros and cons.
+ Plays super nicely with Focusrite interfaces, I run it with my Clarett 8pre, and aside from some faulty settings that were my fault, it was basically plug-and-play.
+ Easily runs multiple effect chains at once. You can chain any number of units that fit in it, stop the chain at any point, and have single units and/or other chains in the following slots. Great for setting up two individual live vocal chains, for example.
+ You can record a signal from any unit, chained or not/any unit at any part of a chain into your DAW. Perfect when for example running a compressor on vocals, but want the uncompressed signal recorded as a backup.
+ Controls are super easy. I, as a complete noob who has never used outboard analog gear figured it out immediately by just looking at it. No fuzz. Just throw a switch to the mode you want, chain it or don't. Done.
+ Allows you to use all 8 slots at once while still keeping all the inputs usable of the Focusrite Clarett 8 / 18i20 as long as it's configured to run 44.1 or 48khz. This was just a thing I assumed would work without looking into it, but do keep in mind that you need 4 optical ports (2 in, 2 out) on your interface to run all 8 slots if you intend to record in sample rates higher than 48khz. The Focusrite Clarett 8pre and 18i20 only have 2 and will only have all ins and outs available at 44.1 and 48khz.
- Being a separate unit from the R8. I understand that being an ADAT or an Audio interface requires different stuff inside, but I personally had a near meltdown over what unit to choose between these two and if one unit could act as both for a higher cost, I would have picked that one any day of the week.
- Separate power brick. All other rack units I have come with the power supply built-in, this one comes with a hefty box that needs to be stuffed somewhere. I have a hunch this may have been done to avoid signal interference, but that is just a guess. Regardless, it's a bit of a hassle.
- (Nitpick) The knobs on it feel different depending on what they do. I assume this is simply due to some being analog, some digital, various types, etc. But some of them feel premium, others feel kinda crappy. I wish they were all smooth, consistent, and had that nice level of resistance.
In conclusion, I really like this product and how it integrates digital connectivity with analog gear. It's really fun to use.