The UK Hoover Turbopowers...
were very popular machines, but hellishly noisy. Not really problematic,
They had apparently, 25% more suction than the old 'Senior' series.
For uprights, Hoover made the best; Electrolux made good cylinders.
You could purchase individual motor parts, whereas Electrolux's 500 Series had to have a whole new motor fitted.
I had an Electrolux 550 that developed a worn motor pulley, causing the belt to ride across and cut into the plastic casing. It did it again with the second motor, so the next motor fitted was for a 610, which had a small pulley fitted to it. It too, was showing signs of wear, so the machine was sold on.