We have a bunch of Nissan commercial vans. They honor the warranty as well. If we follow the extreme maintenance schedule. I can't say I know of any manufacture that wouldn't cover warranty for fleet vehicles. Wonder why dealerships have fleet departments then? We must be special cause we even managed to get warranty repairs on a forklift!
With the 2 failures you've seen do you know what happened to them or did the just replace them and send back to Mitsubishi? 2 of mine had a thrust washer on the input shaft housing fail. Not sure about temurature, on died in summer I think and the other on a nice day in the winter. The third one just made a noise but still worked fine.
We only every had one Chev car that I've seen here, it was a pos 14 spark. Got rid of because it spent more time getting WARRANTY REPAIRS than it did being used on the road. The spark had the same jatco cvt as the Mirage, I wouldn't doubt if the versa does too.
The other Gm's I work on lasted over 400k before the trans piled up(6l80e). Another has over 650k kms/400k miles on the original engine(4.8l). Still runs great.
I wouldn't hesitate to buy a used one. They are easy to replace, no different than any fwd automatic. Drain the pan, pull the axles,pull the starter, shifter cable, all the speed sensors, round wiring plug for the valvebody near the dipstick tube(they suck to disconnect), undo the torque converter bolts, drain the rad, disconnect the cvt cooler hoses, support the engine, undo the lower trans mount,bellhousing bolts, upper trans mount mount. I pulled the subframe as well, it isn't necessary to do that though but made it easier to get to some of the bolts and drop the trans straight down.
If you buy one from a wreck make sure the case isn't cracked before you pick it up or install it, or atleast get the yard to verify it isn't damaged especially at the rearmost part of the case. The lower dogbone mount bends like a straw in a front end collision and the trans will push into the rack and pinion cracking it.