Pros: Quiet, compact, efficient, flexible.
Cons: May depend on the installation. Can be expensive.
Had this installed 5 months ago in October 2010 in cold winter Canada. Two story house with basement so three heating zones, Has handled the cold weather no problem. Wall installation has freed up much floor space in utility room. Very quiet compared to the large1978-ish boiler I had before. Have no doubt this unit will pay for itself over the long term.
Installation took longer than expected. Every boiler installation is different depending on where current piping is, gas pipe location, proximity to a suitable outside wall, and drain, etc. My piping was a litle tougher just because of where the boiler had to be mounted, but it turned out okay.
Only issues I had were related to the installation and set-up. At first set-up the electronics unit was shot, but the installers caught this and replaced it with no further issues. The flow detector switch on the recirculation line needed to be adjusted a couple of times. The switch was not adjusted to be sensitive enough at first which caused some puzzling downtime, but since it was set at a high enough sensitivity we have had no problems whatsoever.
My Trinity boiler is also set up to heat a water heater to supply my hot water, and I find it works very well for that, AND it makes my hot water heating high efficiency as well. FYI if you need to heat anything else, (i.e. you built a garage and want to heat it) you can run an additional line out to the garage and then your garage heat becomes high efficiency.
Make sure you install your boiler with plenty of time before winter, so any issues can be dealt with before the cold weather sets in.
Installation is everything. I read the installation manual myself before it was put in and checked on things as it was being installed to make sure it was being installed according to the manual and any applicable housing codes. Exhaust, intake, and drain piping is particularly crutial. The company I bought it from also did the installation, set-up, and follow up, and these guys were terrific. Like anything, make sure the people you pay to do the work have good references and do a good job.
If you have a boiler and need a replacement, or are installing a boiler in a new house, I would highly recommend this one.
Of course forced air is a simpler set up. All there is is a motor, fan and heater. With a boiler there are pumps, flow rates, valves, pressure, and temperatures that are monitored, but I have experienced pretty much carefree operation so far. The unit automatically senses all this info and operates smoothly and safely.
Personally, I would not choose to have hot water heating, but the house we bought had it already and it would be too expensive to install the ducting for a forced air furnace. I would rather have forced air because you can install central air conditioning.
It is amazing that all the heating for the whole house, including the hot water, occurs in a small chamber about the size of a large coffee can! And after continuous operation for hours (when it's -33 degrees and windy outside) the exhaust pipe is just warm to the touch. Now that's efficiency!