I "had" a HE5000 for almost 2 full winters. I just sold it and purchased a larger unit (non-gasser) to handle my heat load. The Wood Doctor is a well built unit that did what it claimed to do, but as with mostly all OWB's the heating potential claims where a "bit" overstated. It was undersized for my application and because it worked so hard to keep up, I was stuffing it full it 3 times a day and having to wait till 11pm or so at night to fill it to get an overnight burn. When it got cold out, the fan "never" shut off. This I feel was my major problem because I think most of my heat was going out the chimney. I will also agree, wind seemed more of a factor than temp on the performance of the boiler.
Don't get me wrong, I feel the HE5000 is a superp boiler and would recomend one as long as you are going to heat within it's limits. (this stands for any boiler).
I saved over 11k in propane bills in 2 winters with mine.......it owed me "nothing" when I sold it.