The 800s are proving to be fairly reliable and long-lived, but I don't think they can equal the rugged simplicity of the 940s. If you're familiar with servicing your 240, you'll find the 940 to be very similar - same engine and tranny family. My wife's '93 940 has 150K miles on it now, and in the 2 years we've had it, it hasn't needed a bit of extra maintenance - just normal fluid/filter/spark changes.

Coupled with the fact that the 940 can be had for less $$, the parts usually cost less, and the overall refinement of the design, IMHO, I'd go for the 940 for the best value and longest service life.