Considering a lot of people in the trade were underwhelmed with these when they first came out (comparing them against the likes of the Contour and Airstream), they actually turned out to be pretty robust cleaners. As long as the bags and filters were changed as recommended, and the brush roll kept clean, we never experienced many issues with them.
I do remember when the bagless versions first appeared. We all let out a collective groan, because this style of dust cup had already been used on the Power System bag/bagless combo, and was nothing but trouble then. Sure enough, it worked just as poorly on the Eureka type cleaners, and irate customers kept bringing them back with clogged filters and screaming motors with ruined bearings. Absolute crap.