I looked at this tank a couple of years ago. Sounded like a good idea; but after thinking it through, I didn't want to reduce the amount of propane we carry by half. Also, when I checked with TransferFlow for details on ordering, they said that the price on their Web site was incorrect. The cost given to me on the phone was about double what I saw on the Internet, which makes me think they had accidentally posted the wholesale price on their site. When I checked their site again the following day, the price had been removed.
For us, a six-gallon marine outboard gasoline tank turned out to be much less expensive (around $35), and it doesn't reduce the amount of propane we carry. Also, besides generator fuel, the portable tank is much easier to store and use as an emergency backup for our TV, especially when we don't have our Bambi in tow.