I have 2 Honda 200Xs, Honda 200S and a Honda 110. Love the 3-wheelers. Rode my buddy's Polaris Sportsman and hated it. Too big, bulky and awkward. At low speeds the 3 wheelers will turn a lot shorter and if you manage to roll one on top of you(speaking from experience), just kick it off - they usually weigh less than 300#.

 

ive riddin dirt bikes 4 wheelers and 3 but i have to say i like 3 wheelers the most i ride a 200m it goes through stuff u wouldnt believe , if u get one be carefull dont put your feet down and take turns slow at first get used to it , its all about shifting body weight. good luck kid

 

Most people that have owned both will tell you that the 3 wheeler will go places that 4 wheelers wont. 3 wheelers dont have nearly as much power but I've pulled my mini van up a moderate grade with my 200M so thats good enough power for an old guy like me.
Lets have a hypothetical race... 3 wheeler vs 4 wheeler through 1 mile of dense bush.
My moneys on the 3 wheeler by a long shot.

 

as far as the 3 wheelers not being as fast as todays bikes. i just like to say i raced my friends 2006 yfz 450 thats piped and i smoked him on my stock 250r 3 wheeler. there harder to ride but if can ride them you can ride anything