I bought this unit
http://www.jlaquatics.com/product/ro...+-+50+GPD.html
2 years ago when Vancouver had a brown water problem. (it was an excuse to get one, my old one was a bare bones unit... crap...)
It's been fantastic, have yet to change the membrane, only the carbon and particulate filter.
Mind you Vancouver tap water shows 16ppm so there;s not a lot to remove to begin with.
It's the cheapest of the bunch, but I find the build quality to be more than adequate. it's hung on my wall in the laundry room, no problems.