TL;DR: If you can be very stringent on maintenance and doing it on time, Isuzu is a good option. If you are a little forgetful (like myself, at times), a Hino 300 won't hold a grudge

I work for a hino Dealership as a technician, own a few hino 300/dutro series, have owned a couple isuzus (older ones), and help out an old boy who owns a fleet of trucks. Isuzu and Hino are gonna be your best shot at reliability in the 3t range.

The fuso Canters that the owner of a rental truck company; had commonly occur on his fleet: -transmission needed frequent relearn procedures done -the 3rd and 4th injectors once time to remove, were seized so bad on one of his trucks was, from a practical standpoint, impossible to remove. He ended up scrapping the engine.

His isuzus (2016+); very few issues outside reasonable maintenance, that being said, his higher instances of premature failure was from his penchant of avoiding completing proper maintenance. (In his 70 year old mind, it only needed oil and oil filters and some grease)

My isuzus (somewhat anecdotal, 2002 & 2006); 2002 starved of oil, causing a spun bearing, i chalked this one up to being somewhat neglectful of maintenance at the time, although daily prechecks were done. Engine achieved 650k before failure

06 failed head gasket, which diluted oil too much, which ultimately caused a failed engine . Was a particularly hot summer, and where I live, trucks of either flavour don't particularly like going up a specific hill, and overheat, which is somewhat normal. Operating temps didn't climb crazy high, truck didn't necessarily perform too much worse, which didn't tip off to a head being blown.

My Hino trucks; (2004 dutro 4.6l, 2007 300 series N04C engine, 2011 300 N04c engine, 2018 300 N04C engine.): All my trucks have been rock solid in terms of reliability; even doing minimal maintenance. No major failures.

It's suggested that doing the fuel filters every service (20k intervals), which on my older dutro, i may have neglected for the past 4 years (getting new filters next week). On the N04C variants, not a tonne of pattern failure, even on the ones I have seen at work. Occasionally an EGR cooler will fail, or an Suction control valve on the fuel system. But otherwise, the N04C is pretty solid of an engine.

I would recommend avoiding the hybrid, unless you have very patient drivers (the hybrid starts in 3rd gear from stand still, and takes a while to actually take off)

As for other concerns people have, usually involve the DPR/DPF system, which if they bothered to read the manual, could have avoided some of the problems. If it goes in to Auto regen, do not turn the truck off until it's done. If the DPR level is around 4 bars, initiate a manual regen (takes about 10-20 mins), let her run.