Stuart, I've got a Storm, not quite sure how much they weigh but i would put it around the 55KG and although initially i thought there is no way i'm doing flats with this when i first got it, i now regularly clean 1st and 2nd floor flats, quite easy to pull up stairs on its large rear wheels, i found my previous Scorpion although lighter and a great machine was more difficult to get up stairs due to smaller wheels and long wheel base. The water pump on the Storm is towards the front of the machine and it does have the tendency to pull forward however you soon become accustomed to this. I'm 46 years old 6 foot tall and around 13 stone and would not class my self as muscular or particularly strong, so if i can do it then any averagely built bloke should have no problems. On top of all that the Storm is a fantastic machine, had mine for 20 months now, no problems.