I just started to use one. I really liked it after the first session. Also my mates enjoyed it.
I wrote a review after the first session but in Hungarian: http://aendorphin.com/rrd-obsession-mk10/
(maybe if you try it with google translate, you will understand something)
SInce then I used it in super strong wind. Jumped as high as never before.
Planning to write a review about it soon, but I would like to test other sizes, and other conditions before.