Please count me in. I recently purchased a 'new' WT550. I say new, because it was a return and the previous buyer scratched it up a bit. (I'm guessing from racking)
It was one of those things where I was trying something else out in the shop and a WT550 just happened to be set up for demoing. As a plus, it was set up to connect with various Epifani cabs, which is what I use. Over the course of a couple of hours on two separate occasions I was struck by the warmth plus clarity - if that makes any sense - of this head. I didn't 'need' a new head (like that has anything to do with anything) but I didn't really want the spend the money just now. Then, the owner of the store told me about the discounted price due to the scratches. One thing let to another and I ended up getting it.
I have been very pleased with the sound of this head so far. There are two minor nits about it though. The master volume is a bit noisy, which surprises me for such a new head. The other is the fan. I don't play all that loud in rehearsal, but it is obviously loud enough for the fan to come on. However, within a few seconds after I stop playing - it shuts off. It's racked with free space over it and is driving an Epifani UL410 - 4 ohm. It just seems a bit sensitive to me. I really do like the sound though, and I've owned a ton of gear over the years.