Hi Curious Minds!
I have been happy with my experience with Flysurfer kites for nearly 4 years and am happy to share it.
Main advantages (no specific listing order) of a 10 m Speed (I can only comment on the first generation of Speed as I have not tried the Speed2)
1- great upwind ability;
2- tremendous increase of power with speed... resulting in more speed... thus more power... thus more speed... and so on! Adrenaline rush garanteed!!!



3- great for jumping high;
4- easy care kite (small volume to carry on a push bike, no pumping, line always attached, quick to set up and self-launch, easy/safe self-landing).
If you do not like the above way of kiting, do not choose a Flysurfer Speed!
My Speed is nearly 3 year old now and still look -nearly- like new: great engineered kite, high quality, long durability because (i think) no part of the kite is under high stress:
- the stresses coming from the lines are uniformly distributed to the canopy through numerous attachement points;
- the leading edge is not stressed by the pressure of bladders;
- each line is connected to the canopy via a 'little connection line' that breaks under abnormal stresses (>30/45kg) before the canopy is damaged.
The 10 m is my prefered toy. At 80kg, I use it from 13 knots on a big board (Nobile 132x41) and from 15-18 knots with a fast board (long and narrow, old Airush Switch Pro 147x33) up to when the sand is blown 100 mm above the beach surface (up to 22-24 knots?). If I want to kite below or above this wind range, I use another kite size for more fun.
I also have the 13m Speed. I reserve it for sub-15 knots wind, because this kite pulls like a truck. However, before I got the 10 m, I used to take the 13 m in winds that nearly blew the sand above the beach surface (18-20 knots?). The 13m is a different style of riding: much slower kite, way more powerful than the 10 m: just ideal for a quiet light wind session.
Ok, I hope that may help.
Cheers
Fred