Just my two cents to help...
I am a forced air guy, but I work with some of the best guys in the country. It's been my understanding that the Veissman is about the best $$ can buy period. It's also been VERY apparent, that when radiant is involved, you need to find a very,very good contractor to handle the job right.
I would say that my second choice of equipment would be the Buderus.
Tekmar controls also seems to be the standard amogst the high end contractors as well.
Again, finding the right guy to do the work is the key to happyness !
Hope this helps.