Home Heating tankless Combi Boilers

Hello Everyone,

With so much info out there on the internet, I thought I'd try to narrow this down with recommendations from our community forum, so does anyone know what manufacturer of tankless water heater systems (combi boilers) are most reliable?  Also, what are the names of a reliable HVAC companies with certified installers and experieced techs handling these type of systems. I appreciate any info anyone can share on this.  Thx! 

Be careful of this one. Our water has lots of minerals that clog pipes. Our system in Millburn was ruined in about 5 years.