The good:
Nice clean preamps and eq, low noise, hpf on every input. Great to adjust headphone mixes instantly with zero latency via the aux, great setup to record live gigs with just the desk and a laptop if you only need 2 monitor mixes. Mono and alt monitor switches removes the need for an external monitor controller. If you have outboard compressors it's a piece of cake to use them as inserts in pro tools.
Dead stable with my Mac Mini running PT10/11, I'm tracking 16 channels of drums as 64 samples no bother, not been brave enough to try 32 yet!
I LOVE being able to track drums with eq on input, or doing vocals/bass with a compressor on the insert. Really can't live without either now.
Downsides:
No pads or phase flip on input. I can get around this using some XLR phase reversers and in line pads though. Minimum input gain is 6dB, so not as bad as the low end Focusrite interfaces, but can be a bit too hot for some drum spot mic's.
I've never managed to get the MIDI control working with Pro Tools. Went through the instructions step by step and nothing seemed to happen. Maybe should try again and get on to support as I'd like to even just have the transport buttons working.
I've had to replace a couple of bad pan pots and an eq pot in mine. My local store did it for free even though it was out of warranty as they felt it shouldn't have happened on a desk thats only a few years old (though I did get it as a ex-demo from A&H, so it might have had a couple of years on it already by the time I got it) I've currently got a bit of noise coming from one of the faders that I'll need to look at.
Generally I don't find this is a common occurence on other A&H desks so I think I may have just been unlucky tbh.
And I wish it had SPDIF so I could digitally reamp through my Kemper.
Overall I still love the thing and what it's done for my workflow. I'd like to upgrade to the GSR24M in the future if I can get busy enough to justify the cost.