First off....WELCOME TO THE OUTDOOR WOOD FURNACE FORUM!!!!!!! I'm not yelling, just making a point.
Wow...that is a loaded question. There was a suggestion on one of the banner pages here discussing just this same issue. Phin Phan brought up the idea of having a page discussing what to look for in purchasing an OWB. There are but two pages of suggestions, which you may want to read over.
I will go with my personal experience and I'm certain ore will join later. Many folks on this site either still have to work for a living or they are out cutting wood.
I looked for about two years before coming upon my decision, but my decision was based upon cost of the unit and installation as well as I wanted the entire thing done by the company/brand of my choice, due to my physical capabilities.
After looking into Central Boiler and Royal American and pricing out there COMPLETE package...I decided that we would have to live in this house for 50+ years to even think about recouping monies spent.
We have a 3700 sq ft house along with a 1000 sq. ft shop. The hose is VERY WELL insulated, the shop not so much...but for this year, we were only concerned about heating the house.
Quick note here...you ARE doing something I wished I had done prior to my purchase.....coming to this site and reading EVERYTHING about the brand of OWBs listed on this site. You might also look over:
www.arbonist.com lots of info there as well on OWBs.
Upon doing my research, I decided to go with a Shaver OWB because of cost. This furnace is the bare bones deal, but there are options available with this unit. The total furnace, not counting the under ground pex or installation cost me $5800 and I went with the Shaver Pro Series 250. This company gives you two choices of fire box thickness and as I said, it is bare bones...but just being on here for the past 3 months, I've discovered just how to make this unit run better. You WILL find this site has amny knowledgeable people on it...take it all in as you WILL learn. Side note here, the other reason I went with shaver is that i will recoup my initial lay out of funds in about 5-6 years.
I will step down now and let the next fellow come up and tell about his OWB and why he chose it.
Good luck in whatever you decide, BUT remember to come back here often and just sitting and reading is very relaxing not to mention all that you will learn.
One more thing before I go...where do you reside in these United States?
Lugnut