I've had nothing but problems with my Alpine 150 (I got it at a large discount when switching from oil to gas). From finding a qualified installer to install it correctly, to finding that the installer grossly oversized the unit, and now problems with reliability during Sandy when the control module was fried and I just spent more than 3 weeks without heat or hot water. Burnham from a customer service standpoint has been very unhelpful. I would not recommend becoming a customer of theirs.
If you can overcome those issues, my Alpine works great with cast iron high mass baseboard now that I got all the tweaking done.
My dad installed an ES-2 boiler last year with outdoor reset and has had zero problems with it.
I did see this the other day at my local supplier
It has the primary loop contained within the unit which makes install much easier and will cut down on the cost of extras.