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.
Cheers,
Gable