Well I'm not counting leaks on the rotopax due to seal failures, I think there were two of those and I chalk those down more to my ignorance and not inspecting the seals often enough. But since then I do keep spares and regularly change them as necessary. I have had 6 of the 2 gal units and probably 3-4,000 miles of riding with them on a sportsman 500. I use 4 of them double wide and two high for a total of 8 gals of fuel. I got to 6 after I replaced the two units which leaked (over a year apart). The failures I refer to both happened at the joints where the cans link together. I have used them in ambient temperature ranges of 10 to 110 degrees. On some days we could have a 50+ temp swing - high desert and mountain days and nights. Hard riding on rough trails doesn't help either. I vented them regularly, but there have been occasions of severe swelling.
Based on using other plastic gas cans, I do think the Rotopax's are probably the most robust, and I might not have had the same issues with 4 gal tanks.
But on a quad if I have a leak on a can stored in front of me, I can detect it, stop (optional step I guess depending on severity

) and dismount a lot easier than I can strapped into a 1K when I can't even see the cans and any smells are swept away behind me while riding.
I think the best option for using Rotopax might be in roof racks like some forum members have. I'm tired of people saying don't put fuel in the beds (and I agree wth them), but where else can we put it if we have a passenger, and 2 gals of fuel just won't cut it! I'm 6'2" and my 15yr old son is 6'4" so behind the seat isn't an option. After a couple of early & lucky scares and diligent friends preventing catastrophes - I've kept gas cans out of my rig. But if I want to use the 1K for long rides (the way I intended when I bought it) and join friends on a 1,400 mile round trip from Nevada to Montana and back (they ride quads), I need to find a way to get another 10 gals on board to cover the longer legs and potential detours. Hence my comments about a fuel cell - but we're back to the bed location.
Safety has been a big part of my professional career, and I understand that all risks can't be eliminated, but they should be managed. For me it's about likelihood of occurrence, and severity/consequences of outcome. Look I'm not interested in staying home on the couch, we're adrenaline junkies who ski chutes and trees. But when high probability (when, not if, a leak happens) of potentially fatal outcomes involve my kids, I need better risk mitigation. It's not about the money.
Guys, it's late and I've gone on too long - thanks for the tips on other brands and types, although I hear about leaks with metal cans also, I will give those a look too. A couple of gals under the seat does not seem worth giving up my second battery kit for either.
I love my 1K, but this is a key part of the puzzle I need to figure out. I'll be out of the country on vacation for a while, so bear with me if I don't respond to further comments or suggestions for a bit.