Hi,
I am 90 Kg and 192cm. I learned on a Moster 185cc (Skyschool machines) then flew my own Polini 190 for 18 months and now an AC Nitro 200. So all 3 of those you mention! All these engines have great performance and are definitely great for 90 Kg.
I don't think there is much in it between all them. All 2 strokes take a little looking after. Always use top quality oil and be extremely careful when re-fuelling. Use a filter, such as Mister Funnel when adding fuel. After fueling, make sure the funnel, pipe etc are immediately covered as the remaining fuel quickly evaporates off the surfaces and then leaves a nice sticky oil that is perfect for attracting dust. Next time you refuel, the new fuel washes in any dirt!!!!!
I can't fault either Parajet or AC for service when something is needed.
Good luck, Andy