It's looks like a good system... The sytem coats $75 and the filters are $30 per (6 month usage).
I use a $25 Omni whole house filter to filter the water to the entire coach. I can get 2 pack filters for about $9 and I change them every 3 months.
I installed a $160 Watts RO system under the sink (3 filters, a membrane-the RO part and a final filter) so I have crystal clear drinking water. The replacement filters cost $30 for a 1 year supply. The RO membrane is replaced every 2 years and cost about $30.