stee6043 said:
Perhaps there should be three things to consider:
1.) How much money do you want to spend.
2.) How much space do you need to heat.
3.) How much wood do you want to burn.
From these you can probably make a pretty good assessment of where you should be looking for boilers. You may also want to take a look at some of the hearth.com sponser websites. Cozy Heat in Northern Michigan has quite a selection....
I might add a couple of additional points-
4) (a) how much comfort and convenience do you want
(and)
(b) how much do you want to try to avoid use of other energy for heat as much as you can
especially if you have a personal schedule that will have you away or not able to feed the fire often (a gasifier + storage opens whole new doors in terms of having heat for long intervals between fires)
and
5) how long do you plan to stay in your house? A gasifier will cost more, which may change the payback horizon, on the other hand, it may add more value to a knowledgeable buyer- only you can try to use your own crystal ball to foresee what you think will happen on these points