For the price, it's great, I must admit, but the control software has a quirk which cost me a day. So If you want to control the 18i8 from the focusrite software: beware:
There is an INPUT page and an OUTPUT page in the software. They are VERY BADLY named. Insanely badly named.
The INPUT page refers ONLY to the first four inputs 1 - 4 . Basically it refers to the inputs on the front of the interface ONLY.
If you want to control the other 14 inputs, (The 8 ADAT INS, the two SPDIF ins and four analog INs on the BACK of the device) you actually do that from the OUTPUT page. (Really, you can't write this s**t)
Other than that idiocy, the front inputs with the AIR function sound really great. The others sound good also as you'd expect from Focusrite. It's good gear.