I ran the MiniDSP 2x4s in my last setup, and still have 2 left from my old setup I will most likely use them until I get 2 of the 8x8 kits to use for 7 bi-amped channels. I had a xilica 3x6 for a while, and it was great, but maneuvering through the menues on the screen was a pain, and I would end up using my PC to get me where I wanted, and then take over on the front panel. I decided to sell it, and go MINIDSP, and have been happybever since with the MiINIDSP crossovers.
I have a few MiniDSP units, a 5x10HD that I really like. It's great for prototyping systems....read attempting nutty ideas. Especially with horn systems, it's great to be able to dial in a hacked together 5-way system by ear, then measure, then tweak, etc. Being able to adjust crossover points, slopes, eq, delay, etc. all on the fly is hugely convenient.
I also own their UMIK, which works very well for measuring response. With the free REW, it doesn't take you long to get up to speed on measuring everything you could want. In room frequency response of horns, drivers, systems, my jerk cat yelling at me in the middle of sweeps, etc.
You can use a 'standard' MiniDSP 2x4, etc. to adjust crossover points,slopes, etc. Then take measurements of the system in room with REW and a umik (or similar), to 'correct' the response for your room, listening position, etc.
The active room correction however, needs a Dirac series box.