This is a fantastic little unit that is very easy to use and amazingly priced for what your getting.
Lets start with the size. It is essentially a digital 3u stage box with all your ins and outs llocated on the front of this box. It comes with its own rack ears if you want to rack mount it in a 19" rack case (which is what I did for easy transportation).
Once you have plugged all of your ins and outs into it, then all the operation comes from a wireless device such as an iPad, laptop or android. The unit has its own wifi router so connection to a device couldn't be simpler.
The free app that runs the unit is fantastic. Very easy to use and logical and contacts some great effects units such as reverbs, delays, compressors, and eq's. It is also very easy to route monitor mixes to any of the 6 auxiliary mixes.
A few negatives not so much about the unit but in functionality and in use. Firstly, because i have a slightly older iPad, it doesn't quite keep up with the app and the XR18 which (I assume) requires a very fast CPU to run it. I would like it to be a bit quicker and it sometimes loses connection and can become a little bit clunky. I don't believe this to down to the actual unit, more about my iPad but it is still an inconvenience when trying to mix live. I would recommend running the app off of a laptop or a newer, faster iPad.
My other comment would be that it is very difficult to get a great easy sound and setup quickly. I, like many run a function band and whilst i do the sound, I also play piano. Before with analogue desks this was easy as you could set it all up in sound check and merely tweak it throughout the performance. This is much harder with this unit. The way around this is to rely on presets prior to your gig. Get the mixer set up as much as you can including auxiliary mixes, effects, eq's and then save that as a preset. Then its much easier to tweak throughout your gig.
Overall, its a fantasict unit that i think is really going to change the live sound game. Bearing in mind its a digital desk for under £1000 and a good one at that, i think this will be a very popular product. The other note I must add is that when I purchased mine, you could not get them for love nor money in the UK. Everywhere was sold out and had unrealistic wait times.......everywhere except Thomann. I ordered mine and had it within 5 days. Very happy!!