Not boilers as such, but up till I finished at the pit I had several solid fuel units with back boilers and we never had any real problems with them, both with regards to domestic water or central heating. We never had problems with fuel as we got a coal allowance of 10 ton/year which was more then ample. The big disadvantages were (1) having some where to store your fuel, solid fuel is quite bulky and needs to be stored in a dry place (2) disposing of the ash and the dust produced. Some of my friends had free standing boilers and most seemed quite happy with them, especially if they had an attached garage or a building they could use as a boiler house. Most of the boilers burnt anthracite pearls and were hopper fed with a full hopper lasting 2-3 days depending on usage. Its over 23 years since I last had solid fuel so I'm sorry I can't give you any idea of the price and running costs of modern SFB but all in all I never had any major complaints with solid fuel apart from the ash problem. I nearly forgot the boilers were worm fed and had a shear pin in case anything got jammed and if that happened you had to clean the hopper out to replace it which could be a bit of a job.