I got the G2 tankless water filter. Excellent water filter. The ppm reading for my tap water was around 438. After installing the filter it reads 50-60 ppm and the water tastes great. It was easy to install and does not alot of space under the sink.
They also have excellent customer service. I had some concerns after I received the filter. They were resolved in a swift manner to my satisfaction.
Still have to see whether the filters last for the lifetime advertised on them. But no major concerns so far.