i also have a 572, and despite the limited tube availability, its a keeper...drives the piss out of WP6s and makes them more musical than i (or any of my friends) have ever heard wilsons sound. OTOH, the parts quality (other than those wonderful x-formers) is suspect---read this two ways: they economized during production, and parts swapping should net big improvements.
fwiw, i've had some tech difficulties, but nothing that i couldn't resolve myself w/ some contact cleaner.
overall, most highly recommended.
rhyno