Clarksburg,
How do you like the Varmebaronen? Where did you buy it? Dean Zook from Smokeless Heat is only 15 min away from me. If they would have had a lambda unit I think I would have seriously considered one. I was really impressed with their boiler. They seem very easy to clean.
Paver,
I like it a lot! I have a few posts about it here on the forum if you dig around some, but I really couldnt ask for much more. I did buy from Dean, as he is the only Varmebaronen distributor in the US I think. His service has been top notch, I cant praise it enough. He even came up here to NY to help me get it going.
As far as the boiler itself, its amazingly easy to clean. The curved tubes made it a snap. I brushed them out once a week this winter, which was probably overkill, but it only took a few minutes, so why not? Maple is right, that its very simple to operate. Turn on the fan, light it up, and everything else just works. Only adjustment is when you want the loading pump to kick on, and then when the fan and loading pump kick back off. Otherwise, its all pretty simple stuff, not a lot go to wrong. Some of the models dont even have the fan, but you need a tall enough chimney for that.
Im pretty sure that I dont have the boiler "tweaked" for optimal efficiency, but I havent played much with all of the air adjustments because I cant notice a difference myself. Maybe I should just play with it and see what happens?
There was a rumor here on the Hearth forums that Varmebaronen might be coming out with a lambda model in the future, but I have no idea where that stands. Just so you know, my wife can operate this boiler with no issue at all. She was a little hesitant, but when I travel for work she was able to get it fired up just fine for days at a time.
It does weigh less than a lot of other models, but it was still too darn heavy when trying to move it around

There isnt the same amount of refractory as some other boilers, which I thought was a benefit. The combustion tunnel is something that will need to be replaced eventually, but it held up pretty well this year. The thickness of the steel doesnt have me worried, as I think there are a lot of other factors that would go into how long the boiler lasts.