Excellent concept, with a few quirks in execution.
The choice of fill cap is obviously a compromise, one which I feel is unacceptable for a product of this price.
Capacity is not as stated due to the fact that the fill cap is a "push and snap" design.
The fill cap requires so much pressure to snap closed that I must slightly collapse the sides in order to get a hand under the cap so as to gain the purchase required to snap it closed. Doing so limits useable capacity of the unit.
Additionally, the choice of a "snap" cap necessitates additional measures to ensure the cap stays sealed (doesn't pop open) when the unit is under pressure. I believe this is the purpose of the top strap which so many other reviewers state hinder the filling process.
NOTE TO MANUFACTURER: Considering the asking price of this unit, a fill cap which screws in place is considerably more suitable.
Benefits of a screw-in cap:
1. Such a cap would allow the user to utilize full capacity of the unit.
2. Ease of preparation would be greatly enhanced (users with weak hands, arthritis, etc. can have difficulty opening/closing the snap design).
3. The fill hole can be made larger to ease filling.
4. The "carrying strap" can be made longer to move out of the way to better facilitate filling, as it no longer would need to do double duty of holding the cap in place while the unit is under pressure ( should the sealing abilities of the "snap" design become compromised due to wear from repeated openings/closings).
With that said, please note that this is not a negative review. I give it 4 stars out of five, and I certainly recommend this product to others.
The concept is excellent, as it certainly beats going through the trouble of hanging water above head.
The unit operates as advertised (true usable capacity aside), and the materials used seem to be of good quality. I have not had the unit long enough for purposes of determining durability, but the construction (specifically welds/seams) also seem to be high quality.
The unit is lightweight and compacts nicely for storage.
There are already "copycat" versions of this unit on the market. As usual, these are manufactured using lower-quality materials and/or inferior construction techniques, allowing the product to be sold at a lower price.
Personally, I will always opt to pay more for quality, and I feel that this product is the best in its class. I simply hope that the manufacturer addresses shortcomings mentioned in the various reviews before the competition does.