I bought an HBrewO system from them at last year's conference in Minneapolis. (I'm pretty sure the TDS meter was a conference freebie.) I love it. Like Jeff, I'm totally over lugging full buckets or carboys of RO water home from the Glacier machine outside one of our local supermarkets.
The compact size is super convenient. I make RO water either out on my deck, or downstairs outside of my basement. I typically make 15-20 gallons at a shot, which we use for brewing, for our coffee maker, and for topping off our several aquariums in between water changes. I also use my RO water to make up StarSan solutions for the spray bottles that are all over the house. Our municipal water is horrible for brewing. But they only use plain chlorine, not chloramine, so the chlorine is easily stripped out with a carbon filter which is included with the system. When I brew all-grain, depending on the beer I will use our municipal water (charcoal filtered for chlorine) cut with 50-75% RO water. Extract brews get 100% RO water.
My typical RO operation is to use either a bucket or carboy with some left-over RO water from the last time, which I use to prime a syphon between 3 or 4 carboys in a series with Auto-Syphons in between them. That lets me fill all 3-4 vessels at the same time without watching them. I do have a float valve, which shuts the whole system off when it's full. The TDS meter generally shows output water of 0-8 TDS.
Most of the time, the waste water just runs into the back yard and waters the tree and grass out there. I guess I could catch some in a bucket for laundering clothing, but that involves more work than I want to put into it.
If there's a down-side to the HBrewO system, it seems to me that it's the fact that you need to use their proprietary replacement cartridges. So what. I have not done any math to try to figure out how much money I'm either saving or paying extra over the cost of purchased RO/distilled water. It's a matter of convenience for me.
(p.s. We have a 3 gallon Better Bottle carboy in our pantry which we use for RO water to cut our filtered municipal water about 50% to use in our coffee maker. This $10 Primo hand pump works with any plastic carboy.
https://www.lowes.com/pd/Primo-Plastic-Connector-Kit/3172675 )