[Greenbuilding] Solar water heater

[Ian Remmler]

Hello,

I'm considering my options for water heating in a new house.  A
friend pointed me to the SunMaxx TS thermosyphon solar heater
made by Silicon Solar.

http://sunmaxxsolar.com/sunmaxx-ts-thermosyphon-solar-hot-water-kit-30g.php

This looks like a pretty inexpensive option for solar at
$1558.70 (with shipping it will be a bit over $2k).  I like that
the system is passive, except for resistive electrical backup.
One annoying thing about it is that it comes on a frame designed
for flat installation, and there is no option for sloped roof
installation, so I'd have to modify the frame or something.

Does anyone have experience with this type of passive
thermosyphon heater?  How do they compare to drainback setups?
Do other makers have similar products, hopefully that can be
mounted on a sloped roof?

Thanks for any help.

-- 
    - Ian.