Hi there,

I have been riding the 10m Speed4 Deluxe most of last summer. Disclaimer: I have been raving about Flysurfer kites on this forum for about 10 years.
Here's my brief opinion:
It flies well, better than the 10 m speed2 (not deluxe) and the 12 m Speed 3 (not deluxe). You expect that when Flysurfer takes about 4 years to release the next generation of a kite model for a given size. Better means more reactive and lots of control of its power that result in an easy ride (this comment is related to more comments on power further below)
It jumps well, with a good hangtime, not as well as its predecessor in the low end of the wind range, but it is impressive in the higher half of the wind range.
The usual stuff with Flysurfer: easy to launch, no real maintenance on the kite, kite will last more years than you need. In summary, a concern-free kite.
It feels less powerful than its predecessors. It is no longer a formula one / speed locomotive (pick your style), with notably less power generated from its apparent wind than the Speed 2 or Speed 3. All this is logical because the aspect ratios for the Speed4 kites in sizes 10m and below are not as high as their predecessors. The Speed4 in sizes 12m and above (recently released) have a much higher aspect ratio though, so might behave very differently to the Speed4 in sizes 10m and below.
A consequence of the above: The sweet spot for the 10mSpeed4 is more in the higher part of the wind range (unlike its predecessors Speed2 and 3). I mean 25+ knots (excluding gusts), at 85kg, getting old, broken and with some responsibilities. My sweet spot is old school riding fast, lots of power, and jumping as high as i can. Because of its higher aspect ratio, I am expecting that the sweet spot for the 12mSpeed4 will be the low end of its wind range.
Kiteloops: a foil will probably never kiteloop as tight as a 4 lines LEI, because the power from the canopy is progressively transferred to the bar by many bridles. It is just logic (to me). It does not mean that it cannot be kitelooped, but the loops are wide and powerful, going well into the powerzone.
Wave: i am not a wave rider, but logic tells me that a LEI should be better for this task because of their rigide struts. However, playing in waves is still enjoyable at a level below wave-fanatic.
And yes it floats. I tested it from a broken harness.
Happy to detail more if required.
Good winds.
Fred