I have a Willsenton R8 in my second system. IMO, it offers excellent value for the asking price. For comparison, I have had the following amps in the second system: Rogue Audio Cronus Magnum II, Raven Audio Blackhawk III, Rogers High Fidelity 65v2, and a VTL I-85. When talking about sound quality, I will rate the Willsenton R8 to be as good, if not better, than the aforementioned integrated tube amps. However, when considering the build, fit and finish, the R8 is better than all of them with the possible exception of Rogers 65v2 which was built exquisitely.
There are a few caveats though ...
First, the stock tubes are rubbish. Expect to spend at least $500-1000 on better tubes. So this effectively means that the true cost of the amp is really somewhere in the $2000-2500 range. Of course, nothing is stopping you from staying with stock tubes. Don't get me wrong, it will still sound quite good.
Second, with the stock KT88 tubes, the sound is a bit too bass heavy especially in the midbass region. You an ameliorate this to some extent by using EL34 tubes, which is what I ended up doing.
Having said that, this is a very "fun" sounding amplifier. It has lots of power, massive soundstage, and has that typical "lush" tube sound which makes the music sound so satisfying. It does lack the refinement and imaging of better tube amps, but you will really have to be playing in the >$5k range before the differences are noticeable.
In my second system, I enjoy the Willsenton more than the other amps I've owned. I found the Cronus Magnum II a bit too solid-state sounding, albeit it was a great amplifier. And definitely better than the Blackhawk III, which IMO is overpriced for what you get both in terms of SQ and build quality. I also find the R8 to be better than the Rogers 65v2, with the R8 having more power and bigger soundstage. VTL was definitely better but it was a much more expensive amp.
In summary, the Willsenton R8 is very competitive with tube integrated amps up to $4-5K range, provided you replace the stock tubes. But once you cross the $5k range the difference in sound quality starts becoming more obvious -- especially in terms of refinement and palpability.
Hope this helps.