These guys (based in HK) have being doing some of the most innovative stuff in HiFi over the last few years.
While half the community in the UK are stroking their respective beards, drooling over 'single ended triodes' and arguing about what grease to use on their tonearms, miniDSP have been really pushing back the frontiers of what is available for a home user.
Back in the day, these guys would have been based in the UK, probably a bunch of smart guys straight out of university. Now they are in HK. Sign of times I am afraid.
Back to the OPs question, their stuff is great. Earlier modules were unboxed circuit boards and needed a pretty good understanding of filter design and DSP, but the more recent models are much more user friendly and plug'n play. Highly flexible, and excellent support. Their forum is also excellent, with very active participation of users - so if you want specific feedback on a particular model have a look on there.