Like many others, I also use the inline filter on the hose coming in. In addition to price, IMO the bigges drawback to the under sink version is it only filters water for that sink, but you brush your teeth and shower in unfiltered water? I guess you could also brush in the kitchen sink, but seems kinda odd if you don't have to.
2012 Jayco 32TSBH
2004 Ford Excursion
ProPride 3P / Tru Control brake controller
Roadmaster Active Suspension