Our system paid for itself the first year we installed it.
If you have your own wood supply, and we do, it's a no brainer to have one of these as long as you're not in an urban setting.
I'm thankful that ours was purchased a few years before the new designs were mandated in my fascist state. There are some of these in operation near me and reports are that they can temperamental to operate if the wood isn't nearly bone dry.
I’ve also heard that the new EPA standard furnace has to have nearly bone dry wood. I’ve not seen one of the new ones, but driving by the dealership a few times, the new ones look an awful lot like the old ones. I suspect that they just made an add-on that recycles some of the smoke. If that’s the case, an after-market removal could be very simple. In my case, my nearest neighbor is at least a football field away, so with my higher smokestack I don’t really worry about bothering them with smoke. In any case, they’re country people, too, and the idea of complaining about smoke from a neighbor’s furnace probably isn’t a thought they’d ever come up with. If anything, they’d be more likely to comment on how they like the smell of a wood fire.
But, if I were really forced to, I could easily cut the wood two years out and let it sit. The savings in energy costs would make it worthwhile.