Speaking as a fan of the Junior and Senior models, I used to wonder why buyers bought the Electrolux Z500s until I owned one. I found it remarkably light to push, very easy to use, far more compact and "nimble," ironic given Electrolux's far later decision to market such an upright vacuum using that name - and compared to Hoover's models, the plastic on the Electrolux seemed to withstand scrapes and cuts far better, but then that may be down to my usage, later in life.
Even when I got to try the electronic one with the suction control dial, I found it a very effective vacuum cleaner and far quieter than any of Hoover's models. The electronic models also had a far better way of filling the bag compared to the lowly model I originally had (special/catalogue exclusive base Z517 I think.) What I didn't like was the screw fit filter at the bottom of the bin underneath the bag on that model.