I'm debating these two as well. I currently have a V8, and an M-Super. The M-Super kinda dropped in my lap when one of my best friends saw me riding my V8 and that night decided he had to have one, read a review and in a couple days had the powerful Gotway. I went out to help him get started and he immediately crashed the shit out of it. The thing was doing summer salts down his street. He was horrified. His wife was horrified. So he gave it to me to buy for $1000. I took it with the intent of using it to shoot video from, but the first shoot I got on (Shooting a Mclaren 720s) as soon as I bent my knees to get a low angle it would start wobbling. REALLY, REALLY bad! So I'd back off and lose the shot. So I don't love it compared to my V8. What I DO like about it is the solid feeling which I assume is due to the xtra 20 lbs and the 18" wheel, the stability off road and of course the speed. I did get it up to 36mph once or twice (according to DarknessBot) and it was kinda scary! The tilting forward when turning is the dumbest thing E-V-E-R! And walking it is a joke. One time if fell over and started sawing away on my ankle. I had a scab for 2 weeks from the hungry 18" tire.
So I have two needs. One is doing errands, using the Subway, and basically goofing around. Right now that's 95% of my usage. The beauty of the V8 is it's light, well mannered when walking it and the button under the handle is very handy when walking down stairs. What I DON'T like about the V8 is: the lack of battery life, I get cramps from the small pedals on long journeys when I don't wear sturdy shoes (I have big feet) and the lack of power/stability. It's also pretty wobbly sub 5mph, but maybe they all are? Ideally I'd have one EUC that did everything and KS16s seems to have potential for that. My secondary need is filming which I'm hoping to do more of in 2018. The lure of all that power on the Tesla is inviting, and it's only 4lbs heavier than the 16s...But the thought of a unit that might cease up at any time is horrifying.
I got Jason's 2 cents @ EWheels, but I'd like to get the forums thoughts.