I have been using digital room control (really speaker control) for 25 years and the really stunning effect is the laser focusing of the image. After the improvement in imaging the real benefit is in being able to tailor the amplitude response exactly to your taste. In the case of these processors the only thing that "sounds" is the analog section of the final DACs. In the case of a 2.2 system that would be 4 DAC channels. Once you are in numbers you can do almost anything you want without degradation assuming a 64bit floating point operation system. Digital volume is the problem. You lose bits when you turn the volume down. If you start out with a lot of them you can lose a bunch of them without affecting sound quality. My old processor is slow enough that there is loss of detail at low volumes.
I will never live without digital signal processing. The affects on sound quality are such that any analog degradation is trivial, very trivial. In short you will greatly improve your image, you can make your system sound exactly the way you want and you can integrate subwoofers in a heartbeat with total freedom in placement. A really cool effect is, by placing the measurement microphone in various locations you can make the system image anywhere in the room. Obviously it is only at one location at a time but it is a really useful effect. My desk is at the left rear corner of the room. I have that location on a preset and use it when I am working. It is just like sitting in the listening position.
The new DEQX series will be released shortly after beta testing of the software is completed. A number of us will be issued Pre 8s for testing at a reduced price. I was asked if I wanted to do this. Obviously yes, yes and yes. I have not heard back since. This was about 6 weeks ago. The Pre 8 has a complete 4 way digital crossover system built in along with full, computer managed digital signal processing capability. It looks like it is built like a battleship.