Would not purchase anything made by Dyson on principle!!
As with domestic machines you first need to make a list of what is important to you.
eg: lightness, easy to empty, cordless or not, is it just for carpets or also hard floor, do you have a stairway.
Over the years I tried many different types and makes, two years ago, I was given for Xmas the combined upright and hand held GTech, both cordless. At long last I found the vacuum cleaners I needed. Used firstly in my house, with hard floors downstairs and carpets on stairs and upstairs, also the small hand held one, did my car so easily. Then I moved to a flat, all carpet at the moment, absolutely brilliant and so easy to empty and light to move.