I’ve used TacT, Dirac, and Anthem. A few things:
- DRC can be fantastic, especially when using digital xovers for subs. It can smooth bass response, and the good products can also remove excess brightness if you tell them to.
- The better the digital processing in the convolver, the better it will sound. The best of the ones I’ve tried is the Anthem STR, which works at 192 kHz and 32 (I think) bits.
- Different products don't all work to the same level. YPAO in particular seems to have a bad reputation. ARC and Dirac have good ones. Even ARC is better or worse (from what I read and discuss), depending on whether it comes with a subwoofer or a full processor.
- With previous products, I’ve heard minor side-effects when I engaged the DSP. With the Anthem STR, I do not.
- It’s important to have a well-calibrated mic. The cheap items in a manufacturer’s lineup often will have worse mics.
- No automatic system will always arrive at sound the way you want it. Every automatic solution should be tuned by ear (assuming the devices allow that) to dial it in. IME, it can take several iterations to get there.