Lots of power into low impedance loads. Excellent internal construction technique. Poor external fit 'n finish (although, from the pics, their 'premium' line appears to looks quite respectable, cosmetically, for seven thousand dollars a pair). At least questionable use of certain caps in the Hypex modules, which the manufacturer can upgrade for 600 USD each, but at the same time claims that the actual amp's failure rate is very low, and is in any case is not from caps. Making the total for a two channel set up from 5000 to 7000 USD dollars (depending upon one's upgrade path). Less than industry standard warranty (two years v. the typical three years v. five years for Benchmark).
In any large dollar purchase one has to weigh the pros and cons. I don't need that kind of power, so it's not my thing. If I did, and if I lived near the factory (do they even have a 'presence' in the US?), and if they stepped up their warranty game (if their failure rate is as low as they claim then why not add a couple of three years to the warranty?), then I'd put it on my list of things to check out.