Is this Hoover comparable to the Dyson??
Gary,
The answer to that would be NO, the Hoover is light years better than the Dyson, and will last many years longer.
The Decade 80 is a variation on the Hoover Convertible, one of the best vacuums ever made. Your model dates from the middle 80's, and was the top of the Convertible line in its day.
Yes there are bearings in the roller to be greased. Easy job. Parts should be readily available too, either from any vac shop, or through ebay.
Enjoy the Hoover, thats an awesome machine!