Getting rid of my digital mixer and replacing it with Apollo has been great. I have it connected to my 2192 and I have found it enjoyable to bounce out virtual synths through the 2192 and back in again and then add plugins in the Apollo mixer. It reminds me of doing effects in my old 4 track. It's fun and hands on.
The mic pres sound great too. I have a Korby Kat Blue connected to pre 1 and it is awesome. I like having a low cut. I also have a Pacifica pre, but it is so much easier to use the Apollo pre - with the blue 1176 plugin!
I have it installed in a portable rack with the 2192 - so I can take it anywhere with a Macbook Pro do serious recording and mixing.
The only thing I would add is a second quad UAD-2