I got a watts premiere from costco years ago and it works ok. incoming water is around 500ppm TDS(total dissolved solids) in an area that has very clean tap water and comes out about 20ppm(bottled RO can get to around 0-2ppm with the industrial filters) with my water pressure. you need to change the filters once a year or so and I get them on amazon for like 20 bucks or so and a cup or so of hydrogen peroxide to sanitize it. you need to change the membrane every 3-5 years or so depending on water quality and that's about 40 bucks on amazon right now. Whichever way you go, you will want a multi stage ro system with a sediment, carbon (I can't recall which of the sediment or the carbon is doubled up but one is) and polishing carbon filter post membrane.
I used to work on ultra high purity water systems for pharma so I probably care more about water quality than most consumers. If you have more questions ask away.