#1 B7510 has about 670 hours - no major issues
#2 B7510 has about 370 hours - no major issues
B2410 just purchased has about 2560 hours - had major repairs done to mid PTO driveline for its associated front-mount snowblower last year, likely about the 2500 hour mark.
While I'm not worried about reliability, I do like to know at what point things are likely to go wrong with these machines. Some designs have inherent weaknesses that manifest as failures within a certain number of operating hours. I come from the aerospace world where we regularly replace components based on operating hours, since those operating hours represent a certain safe proportion of their fatigue or other service-limiting design factor. As a result of my background, knowing what components have failed for other operators within a common operating hour range is very good data to have. I appreciate everybody sharing their results here.