I got the 4 m2 and the 8 m2 yesterday, and had the chance to ride the 8 in its very lower limit, and a few puffs where in its sweetspot too.
Only used the 8 and 11 one time each, so not much experience in their ranges.
One thing is for certain though, it is the 3 and 4 and 5 m2 that really rocks, they can zip around fast and have loads of powerspike because of this.
Whereas the 8 and 11 are of course light and hangs well indeed, easy to pack down, but as such they are nothing special, compared to other kites, as they turn just as slow, and has no significant power spike.
Good because they cost half of other kites, and can hang in less wind - but other foilkites or one and nostrut tubes can probably give at least the same in terms of kitefoiling
Dont know for sure yet, but seems this way, in fact exactly as tomtom has said from the beginning
3-4-5 m2 are amazing fun kites, and in waves maybe the superior ones out there