some people reported problems with the electronic power attenuation on the AFD100, which isn't on the new 5 watter. i've had no issues with mine, which i've had about a year. Twinfan had one, and he had an issue with the EPA, but if i remember rightly it was tracked down to power fluctuation in his domestic supply, which seemingly can affect the epa, especially at lower settings.
even though i have the AFD100, i find myself very interested in this 5 watter. it would make a very nice replacement for the DSL201 i've been using as a portable amp