We had one when we lived in the Northeast. It was an older used unit we picked up for a song from somebody upgrading to a newer unit. It was nothing fancy, basically these things are a simple boiler unit with a metal shed and insulation wrapped around them.
We saved a ton of money. At the time this was a VERY old, VERY leaky house with an oil-fired furnace. I'm not kidding, we spent $6000 one year (and that was in 2014 or so, so figure like $10000 in "today's money") on heating oil. Granted it was a bad winter but with that kind of spend it doesn't take much to have a payoff for an alternative.
Your wood source can be a big factor here. We lived in the deep woods and had tons of red oak to harvest, which is nice because it's super easy to fell and split. Wood boilers can usually burn just about anything and you don't need to process it much - as long as it's well seasoned, you can throw entire rounds in there, although we'd split a cord or two to help get smaller fires going in the "shoulder season." But lots of folks in NY buy what's known as "slab wood" which is totally different from the $300 "live edge" slabs folks are making tables out of these days. It's the outer few inches of logs cut off as saw mills process lumber. Folks would buy one or two truck loads of this, usually super cheap, and you'd see piles every winter in their front yards if you drove through rural NY. 5 minutes a day with a chain saw to lop off another 2' or so and that's one cheap, easy way to get it.
Installation can be a big deal. I assume since you're asking that your house is already set up for hydronic heating (baseboards or similar). You'll need to trench out to the boiler and it takes a few circulators and control systems to integrate it right. If you have the skill to do it yourself you can save a LOT of money here, but if you don't, it's not something you want to try after watching a few Youtube videos. There are all kinds of subtle problems you can introduce if you make mistakes like using the wrong kind of piping (you can't use normal PEX, it has to be oxygen-barrier, copper, etc), circulators (not sized properly for the load), not properly setting up water feeders, air separators, expansion tanks, etc. If your house isn't already heated hydronically in some way plan on a major addition for that as well - there are water/air exchangers you can add to forced-air systems but they're not as efficient.
In the worst winter we had there, we burned 12 full (not face) cords of wood. The boiler we had gotten didn't have a secondary (hey it was $500) so we found it was best to fully process our firewood, not try to burn whole rounds. It was a massive undertaking and took all summer to process and plenty of time each day during the winter to keep it fed. But at the time, we had very little money and we were warm all winter for basically nothing. I wouldn't necessarily recommend it to anyone, but it sure saved our bacon and I don't regret it.
Would I do it again? We're in a more modern house with a natural-gas fired furnace and well insulated, well sealed walls. I think we spend about $150/mo on LPG and we have a bunch of adults and kids taking showers and doing laundry so a fair bit of that is just heating hot water. I wouldn't do it here. But if I bought some old farmhouse on some acreage? Sure. Absolutely. A modern wood boiler with a secondary can run for almost 2 days on a single load of big rounds, if they're well seasoned, and I'd definitely do it again.