The build quality question is important. But you also need to consider that you need to work with it day after day.
My second question would be how high do you need to lift the 25 litre can to get it onto the trolley.
With the pure freedom, you only have to lift it a small distance.

The x-line looks similar

With the H2 Go trolley, it's rather higher.

The polarbrite trolley is even higher still.

Now of you're 6' plus and beefy, this might not be an issue. But you need to think how you might feel about lifting 25 kg cans of water that high all day every day. I personally think that it might get a little wearing.
And for build quality, you just can't beat the pure freedom trolley.