I never considered roof-mounting on my 2+ story home, 'cause I'm chicken. If you have the room and a unobstructed southern exposure, rack-mounting has some advantages if you can get past the industrial-look landscaping effect. It doesn't take much pressure to run the system (I'm actually getting stronger return flows after installing the solar and going from 1.5 inch to 2 inch plumbing), any maintenance is easier, and if I want I can cover them with a tarp for winter. The disadvantages include potential damage from accidental impacts, vandals, animals chewing, etc.
For the solar panels I set some 4X4 pressure-treated into concrete and built the rest of the frame from treated 2X4's, and 'skip-sheathed' with 5/4 inch decking left over from the old deck. The panels are angled on the frame so they'll drain for the winter. I've strategically placed unions so the bulk of the piping jungle next to the pump/filter can be drained and even taken inside and stored if I want (most of it is attached to a wooden platform for support and stability). I'll feel better with the 3-way valves and motor drive inside for the winter. BTW, the Goldine controller for the solar works great.
Those 4 panels and the solar cover are keeping my pool near 80 deg even though the sun angle is getting low, our daytime highs now are in the mid-70's and the evening temps are in the 50's (we've had a sunny Sept. here). During high summer on sunny days some pretty hot water is pouring out of my return, and mid-80 or higher water is easily maintained during a normal Iowa summer. I'm pleased with the solar system, and especially like the TechnoSolis panel design.
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