You can route anything anywhere with this. I purchased this after much thoughts on the competition (fully analog mixers) and it appeared the best suit for my needs, even though it was the most expensive alternative.
You can use it as a standalone mixer, a USB sound card with onboard EQ and compression, a 16 channels summing mixer... You can also pair it with another device.
Onboard compressors and fixed frequency eq are really limited, they can be useful for minor adjustments but you will probably need other gear or software for tone shaping, I almost never use them.
The bus compressor on the other hand is almost always on, I use it to glue the mix of 3 microphones on a single guitar speaker and it does bring something. A dedicated button makes it very easy to use the bus compressor as a parallel compressor.
I do miss ADAT expansions, but being on Mac I can work around that with either aggregate devices or Omnibus.
I also miss integrated recording features, but nowadays you can connect the Big Six to a tablet and built a mobile recording setup - although you would probably need external preamps as the Big Six only has 4 (well maybe 5 with the talkback input).
Be aware that in order to take full advantage of this beast you will need lots of cables and a patch bay. That is the main reason I cannot really see it as a mobile mixer. Even with a clean cable management it is a small nightmare to unplug it and re-plug everything. But then people complained about the DB25 on the little Six.
