Personally, I prefer the A-9 over the A-10. While I'm not familiar with the pyralin hopper, I'm sure that as an early type of plastic, with regular use it could eventually craze or crack, which would be cause for concern. I like the idea that if desired, the glass hopper on the A-9 can go in the dishwasher, and that if it were to break, a replacement would be relatively easier to find.
Although the seller advises that the subject mill was bought new by his grandfather, judging from its nearly pristine condition I don't think it was in daily use for 75 years, or even 7.5 years for that matter. The hopper on the A-10 I saw previously on eBay had a toasty tint to it from many years of storing beans, which IMO compromises the unit's appearance. Another reason to opt for the A-9 with its glass hopper.
Having said all of that, after seeing the KCM mill that was recently posted and hearing the testimonials about its non-spewing behavior, even with its plastic hopper that's the model I'd prefer out of the three.