I've also used Glacier water, for the past 6 years. 30 cents a gallon. I guess it's riskier than making your own, if you test it before use though, you can be sure that it's OK.
I had a small 5 stage RO
, for drinking water at my previous house, depending on your source water, your main filters( membrane excluded) can bind up, and need replacement, within 5 months. It was costing me about 54 dollars every six months for new filters. Every 3 to 4 years also, you need to replace the membrane too( about 50-60 dollars). In southern Florida we pretty much have swamp water.
Because of these factors, I've just accepted that Glacier water is a little easier for me. I also don't have the initial investment of a couple hundred bucks. The one I had for the house was 500 dollars from the builder,installed.