Hey Zeke,
Back in the day when I was living on the boat, I collected rainwater for drinking and cooking: no worries ( course I did come down with a coupla nasty cases of dysentery in central america, probably from some restaurant- the rest of the cruise around the pacific, no dysentery).
Anyway, here on Saipan we hold the distinction as the only insular area under the American Flag as having an un-potable municipal water supply. Living out in the boondocks, surrounded by jungle we get a lot of crap in the water we collect; decaying vegetation, bird, bat and gecko droppings; and my cat loves to leave dead mice and rats up on our roof.
I've worked on a few R.O. systems on several boats, but found the maintenance considerations too high for home use (and quite frankly the water it produces doesn't taste as good as rainwater). The UV system has low power consumption, low maintenance ( just clean the quartz tube when I change out the particulate filter cartridges and change the uv light tube once a year) and is highly reliable. I filter particulates down to 3 microns, which is probably ok, bit I look at the UV as insurance; When the SHTF I really don't want to worry about trying to get medical attention for dysentery (trust me, no fun at all) or something worse.
I really like the idea of self reliance- producing my own water (rain-catchment and cisterns with UV) and power (listeroid generator with inverter and battery backup). I guess I'll have to learn to write my own books, too.
On a side note, my desire to own a large green engine with flywheels has been realized; my arrived from Anand a few days ago, I was going to have it delivered today, but Typhoon Kong-rey popped up and spoiled my plans. Hope to have it delivered after the blows through and start the tear-down for inspection and moving into the generator bunker.
cheers, fred