Huge channel count, no less than eight AUX out, ten combo XLR/TRS and ten XLR preamps. Two of the TRS can be switched to Lo-Z for instrument use. A RCA (cinch) L-R input pair (making up the 24 analogue input channels). Fully patchable internally. A whopping 32-in and 32-out USB interface. Playback from USB. Recording 24 tracks to USB. Web server built in. WiFi hotspot built in. Ethernet connectivity. That's a huge amount to pack into a 4U rack unit (and it's not deep).
Some weirdness - USB sockets only offer 40mA - this means that powered USB hub is a must. All USB storage must be FAT32 - unless you know what you're doing, you'll hit limits very quickly. Any USB media must be fast enough to write 24 channels of audio while recording. The networking is a bit idiosyncratic too - you'll need to be comfortable with TCP/IP, and WiFi configurations and networking concepts generally to master this device.
But I'm very happy with my Ui24R.
Many thanks for the quick response and help. Much appreciated!