Yeah Buddy,
We have been using one for probably 10 years now.
The black filter style and the after chem. filter PDF I think they call them, the bad stuff lower filter.
When you figure the size you want go one bigger (kind of like a safe).
We have two filters in ours and with Glendale water the filters last about 6 mo. for the two of us.
I prefer it to the Rev. Oz. system for not dumping 30% water in the process.
Filters are spendy, but I also have a smaller one for me mum ( the travel size ) and for her the two filters also last 6 mo.
I told my oldest about them when he was thinking a R.O. system and he likes it as well. He is a fire sprinkler fitter so keep that in mind. They just half to know righty tighty lefty loosy you know.
We have one and swear by it. Kind of pricey up front, but the difference in water quality is AMAZING, and they’re much better and more convenient than something like a Brita. Highly recommended, and yes, go a size larger than you think you’ll need.