We did some research of this subject a year ago.
We were looking for an onboard auxiliary heater that used an existing fuel, was not going to break the bank, and would add to the decor of the boats interior. All the installations I could find were Force 10 or Espar with Force 10 being the least expensive by far and the only one using a fuel that I had onboard already, gas or propane. We thought that the Espar would be classified as a main heat source as opposed to auxiliary and was quite a few more boat bucks. We went for the Force 10. It has since been installed with a ceramic back plate and fits in well with the boats interior. We mounted it on the port side bulkhead with the flue going up to the molded in winch pad that the 30-Mk1 is known for. I haven't run the fuel to it yet but all the folks we talked to said they work great.
Steve Scott

Isn't there a slight difference in price between the two ? There is another called a Fab All. I have the Fab All 170 on my 36 and it really cooks. as i understand it there were some disgruntled force 10 people that went off an founded the Fab All line. If you look at the specs between comparable systems, you can see the Fab All is more efficient. It also can be plumbed into your fuel line. after shopping around, although I live on the east coast I bought it from doc freeman. they had the lowest price

We have the Force 10 on our 29 (also on Superior) and have been happy with it for the most part. The one thing I would point out about it is that it has a built-in oxygen sensor which automatically shuts the unit off if it senses too little oxygen in the cabin. This is good for obvious reasons, but it does mean that you need a source of fresh air coming into the cabin while it's running -- a minor annoyance depending on the outside temp. We usually just crack a hatch and that does the trick. Just something to consider...