I have hydronic in my house, and I'd sure rather have forced air.
In addition to the usual problems of keeping the furnace running, you've added all the problems of pumping water all around. About once a season I have to fix one of the zone valves, and the pump drips a bit--gonna have to change that shaft seal someday...
not sure what you mean by 'usual problems' keeping your furnace (boiler) running? and not sure how pumping water around is a problem?
rarely a problem here with any zone valves (have 3 zones), and any drips (those are rare, too) get fixed so as not to get worse. I'm very pleased with the efficiency and comfort of my baseboard hot water system. to improve efficiency further I installed a natural gas boiler that has sealed combustion with an integral 'indirect' hot water heater. no inside house air is needed for the boiler burner - outside air is drawn in via 4" piping then the results of combustion from the sealed burner unit are vented right back outside via a parallel exhaust pipe. this way my boiler room downstairs is also sealed up to avoid losing heat out a big hole in the wall that typical natural gas boilers/hot water heaters need in order to draw in combustion air.
Roger C H, as far as the KISS principle, you can't get much more so than with hot water baseboard, when correctly and properly installed. The boiler heats the water, the pump pumps it around the system, then repeat as the thermostat calls for heat. No nasty furnace air filters plus changing them regularly, no leaky air ducts, and there's no nasty stuff growing (or small critters dying) in my copper hot water tubing.
now, all that said, there are different systems to meet different folks' needs for a reason, and I'm good with that. and any system will need maintenance of some type - that is unavoidable. my point being to decide what fits your needs and go with it. even if what came with your house isn't working out, it may be worth it for peace of mind to change out to something else if one can afford to do it and depending on how long you plan to live in your house. in the very long term - if your present system is old and inefficient enough - it may save you money to switch, or at least upgrading will make a good selling point for a house in the near term.
ok, back to the OP topic... I'm still working on obtaining my used trailer (it's in process!) and have wondered about going hydronic with heating too (would keep potable separate), but with an anti-freeze solution instead of plain water being in Alaska and all. I am even wondering if it would be possible to try running in-floor 'radiant' tubing instead of just a loop around the outside, after insulating the floor a bit more. just crazy thoughts that are bouncing around in my brain. (now that I read through the links, this 'radiant' idea was discussed pretty well on page 2 of the thread Steve L. linked to. wonder if anyone has tried it despite the potential costs and troubles involved? or maybe it's just a crazy 'pipe' dream?