How complicated was yours? What brand? What building(s) are you heating?
Complicated? Not at all. In fact, I was surprised at how simple of a system it is. The stove heats the water; the circulator pump distributes the hot water to the house; and heat exchangers in the house extract the heat from the water. Installation was a breeze. You'll have more work into burying the pipes than anything else.
The brand is Pacific Western made by Innotech Developments. Here is their homepage:
http://www.outdoorfurnaces.com
I did not do any comparison shopping when I bought. A family member was a dealer at the time, so I went with him. I have the model 2 which is much bigger than what I need, but the advantage is that I can go every other day between fill-ups (this time of year), and once-a-day fill-ups when it gets colder (highs in the low 20's).
I am heating my house (1800 sq. ft), an attached 900 sq. ft. garage, and our domestic hot water. However, I have a family member with the exact same stove and he is heating a 2000 sq. ft. house, his domestic hot water, his driveway (only when he needs to melt snow/ice), and a 60x40 pole barn. He has to fill his once a day now and twice a day when it gets colder.
Other things to think about:
1. You really need to do financial analysis on how much you will be saving by buying an OWB. Factor in how much it would cost you to heat with conventional sources. In my opinion you need to save $2,000 a year for it to make sense. The initial investment is high, and it just doesn't make sense otherwise. Also determine how long you will be living at the house. You will want to stay there long enough to payback the investment plus enjoy a few years of "free heat".
2. Wood. Lots of wood. I burned 12 cords last winter. That's a lot of cutting, splitting, transporting, and stacking. You need to be healthy enough to process that much wood every year. You also need good equipment. A good saw (or 2), a good splitter, and something to transport the wood to the house. If you do not have the equipment now you will have to factor their purchase into the financial analysis.
3. Smoke. If you research on the web you will find both sides of this story. You will hear from one side that they never smoke, and the other side will say that they are nasty smoke-beltching hogs. The truth is somewhere in the middle. Obviously they don't smoke when the blower is off (or the damper is closed in the case of a Central Boiler) which is 90% of the time. However, mine does smoke pretty good for the first few cycles after a fill-up. After that the wood in stove is good and dried out, and a good layer of coals has formed. At that point you will see almost no smoke when it runs. If you have close neighbors you need to consider that because at times it will smoke.
For me it made sense. I have access to free wood. I plan on staying at the house for 10+ years. I already owned all the wood processing equipment. I estimated that I would save $2500 over heating with LP (which was my only other option). And I am in a rural setting with no neighbors close by. But when asked I am very honest that they are not for everyone.