I can only share my experience with the Willenson R8 which is KT88 and EL34. I'd say you get what you pay for. The R8 used is like $1000 and that's what it sounds like. It couldn't compete with the Mastersound, AudioNote, Leben, Luxman tube amps I've owned- but it's not priced like them either.
Maybe consider a used Line Magnetic? The importer cleans up on these but the used value seems more in line with what you are looking to spend and I bet the quality is better.
Just my experience, I sent it back within the 30 day and got a refund within 45 days.