We have been using this for past 8 months and have not faced any issues so far. I know we should be changing the filter in a year, so will comment again once I have used the service. The thing I did not like was that the sales person promised us a 2 free services within the first one year and a filter change. However, when the installation happened there was nothing written in the agreement to that effect. Now the sales agent is not traceable.
So when buying if you are negotiating please make sure you get it written somewhere in the document.