I've had this mixer for 6 months and I have used it on a lot of large & medium sized functions, smaller pub & bar gigs, and even a small multi-band festival. I can happily say it's fantastic and it's handled every event seamlessly and without any problems.
The user interface is very intuitive, I personally prefer it to the apps on the A&H, Mackie, Pre Sonus and Behringer mixers that I am also familiar with.
20 input channels, lots of auxes, USB input for backing tracks & playlists, USB output for multitrack recording, the list of features goes on and on and is impressive.
99% of the issues people have with this mixers like this (with no physical faders, relying on only software control) are 'operator error', so don't be put off if you see some frustrated users on the Facebook user groups. This mixer will reward the user that reads the manual and puts in the time to properly learn how it works. If you think you can just take it to a gig and learn how to use it there during sound check, I guarantee you will not have a fun night.
I would also say that this is not the best mixer for somebody new to sound engineering.
It's worth inversting in a decent router to ensure stable WIFI connection with your tablet(s). I always have a laptop hard wired to my Ui24R too as a back up contol surface. I've never had any problems but it's always good practise to be prepared for anything.
I am writing this during the 2020 Covid-19 lockdown, and I'm keeping my playing chops up every day by playing along with the many gigs I have recorded since I got this mixer. The 'soundcheck' mode is awesome! I can play the gig back, minus the original bass track, and play my bass live along with the band. I'm monitoring /mixing the whole band via an aux with my IEMs in so I don't upset the neighbours. This function is proving to be a life saver at the moment.
Considering the price of this unit, the hardware and functionality that Souncraft have squeezed into it, it's amazing. And it's small and light, only 4U tall.
All in all, in the right hands, it's a fabulous mixer.