I've got 4 rotopax cans and mounts now. I thought they were stupidly spendy, but..... Over time, they have proven to be amazingly adaptable and useful for fuel, water, diesel (for my teardrop diesel heater) etc. I picked up 2 of their gas cans on sale last spring with mounts for $99 bucks so they can be had on specials. Gotta say... They're pretty tough to beat. And, the fuel can spouts actually work and pour liquid. A rarity nowadays.
I've not tried some of the other similar stuff but then, don't bother fixing it if it ain't broke.