Mitsu can be thought of as the old-school tech that you just can't give up. Just my opinion. They're outdated, boring, under-equipped compared to the competitors. However, those guys really know how to screw together a car. Mitsu still builds some of the best Japanese (albeit mostly made in the USA) vehicles you can buy today (disregard the Mirage, that's an outlier). Other than a few design updates, they've basically used the same engine, trans, platform, everything from 10 years ago. Maybe 5, but still. They took a play from the GM handbook: continue to develop and improve a proven and (most importantly, paid for) platform until it's no longer viable.
Look back to the mid 00's, Mitsu used basically one chassis to underpin the Galant, and Endeavor. Little stretch here, little width there, taller springs, boom! We made an SUV out of a sedan for peanuts. Great idea, subpar implementation. Given the prices new Mitsu's go for, I'd have no issue recommending a new Outlander Sport. They're proven, reliable, and they actually have a half-decent CVT trans. Way better than say... Subaru of late. That 2.4 4-banger? Part of the GEMA "world" engines shared by Chrysler, Hyundai, and Mitsubishi. Not without their faults, but very tough engines overall. I would confidently say that Mitsu's version was best, followed by Chrysler's, then Hyundai/Kia's.
How about the V6 option, my personal preference if I were to buy one. The 6B31. Where's it's history come from? Well, the lowly 3.0 V6 that powered my parent's 1994 Plymouth Voyager for a painless 160k miles before the CHRYSLER designed automatic transmission gave up. We sold it to a family friend that converted it into a 5 speed V6 van using a combo of 4-banger manual van parts and V6 Dodge Duster parts. Too funny. The same engine design cranked out 300 HP in the DOHC, twin-turbo 3000GT VR-4. Talk about proven.
Anyways, aside from the Mirage, any Mitsu is a solid vehicle. Parts availability won't go anywhere, they still sell these models globally and they have to support them. If you're worried, take a look at Saab. I can still call up the (once) local Saab dealer and order parts. Bit of a wait vs. a common vehicle? Sure. But they're there. They haven't built a new Saab in a decade almost, so that should tell you something!