I am using Kent Grand RO from last 1.2years (purchased for ~14+k)
- imo its really good and has 8litre of storage capacity
- had some issues with the mechanism which stops water once the tank is full, but that particular thing was replaced (free of cost) with a new designed one and no issues after that!
- regarding service : in delhi/Noida is really good; in BLR it was ok..
Try purchasing it directly from company n u will get good discount after bargain.