I've got two. A super lightweight one (250w/7kg) and a high power one (2000w/36kg).
The lighter one is really a bit small for me. 250w is not enough power to propel a grown adult. I have to assist it up hills, and the handle height isn't adjustable - so it's a bit short. I bought it when I got the electric car as a 'last mile' option - as I had to park the car a fair way from work to charge it. I've handed it over to my son. It flies with him on it.
The bigger one cost a lot more and is a lot more work to maintain. But it's a lot more fun. It's very rare you use as much power as is on offer - I usually ride on a single motor. The only real drawback is weight. Trying to lug an awkward 36kg around isn't easy. I can just about get it up and down stairs - but any further and I'd rather walk. This now has a bigger led headlight and solid + cut out tyres since I took this picture, which are a vast improvement. Since I've owned it I've replaced the brakes and the rear shocks.
Overall I've done about 500 miles on these scooters. Mostly on the pavement, relatively slowly and giving pedestrians right of way. Where available I use cycle lanes and if it's quiet I'll go onto the road. Never had any accidents, complaints or issues with police. I ride carefully and courteously. I've avoided going anywhere near London with it - as this appears to be the main focus of the anti scooter enforcement in the UK.
They're great for using abroad where they're completely legal. For the past few years, I've used them to go short distances with the family around towns in France and Holland. Where most family would bring a load of bicycles, these are so compact they can fit in the boot.