Hmm...
I liked the Turbopower 2/3/1000 machines, they were very well made and worked well. A bit heavy, though, an issue addressed with the Purepower range. My granny has 2 Turbopower 3 Autosenses, one upstairs, one down, which she's had for over 10 years now. She uses them regularly, and they're still going strong.
I think the early Purepowers were the last decent ones. I had one, and I liked it a lot. It was of a good build quality, and worked well. The early Purepowers bear very little relation to the later models, and even less to the Dust Mis-Managers!
It all depends, really, on whether you consider longevity to be the deciding factor. In this day and age, do we want a cleaner which will outlive us? With improvements in technology happening so fast, don't we want the freedom to replace a machine once it becomes outdated? Or are the 'improvements' really improvements? Are they just sales gimmicks?
If Hoover were to make a machine out of componants as high-quality as they did in the 1930s, they'd have to charge the same kind of prices they did in the '30s, ie. £1000+, which would put them out of most people's reach, just as they were back then.