I purchased the system about 6 months ago, so it is probably time to install it :)
I choose to install it in the basement and not under the sink for ease of access and to be able to continue to use the area under the sink to store way too much stuff.
The system we got had pretty good directions and overall the system was pretty easy to install. It takes a very long time for the water to filter, which is why you get the pressure tank.
We went with the 6 stage filter with the alkaline replacement filter at the end. I had to buy a longer water line to get up to the sink on the first floor. Not looking forward to filter replacements.
The water tastes fine, Jen seems happy. The place I noticed the biggest difference was with the ice cubes, they come out much more clear. We had a soap dispenser in the hole that we repurposed, so I kind of miss that. Perhaps it is time to try drilling a hole in granite :)