What contaminants are you trying to remove from your water?
I have nitrate in my tap water. So I use a 75gpd 6-stage RO filter to remove nitrate, flouride, chloramine, metals, etc. HMA will not remove nitrate, flouride, or phosphate. The disadvantage of the low cost RO system like mine is the low on-demand flowrate. So I have mine setup to autofill a Rubbermaid trashcan with a bulkhead installed and external water pump to create an high flow on-demand RO system. With this setup I have 45 gallons available at 5gpm.
The HMA is high flow on-demand (no storage tank required) but only removes sediment, heavy metals, chlorine, and organics.