I want to install a tankless/condensing boiler with an indirect water
storage tank for hot domestic H2O. My first objective is to save space
but I'm also very interested in the increased efficiency of these
units. Direct venting is also desirable for this installation.

Can some of you out there offer recommendations on particular brands?
I am looking at Monitor, Triangle Tube and New York Thermal (Trinity).
Is one of these brands more reliable than the others? Are there other
brands I should be looking at? Any other advice?