I ride a Gaastra Pure 2016 in 13 - 10 - 8 and love the kites to bits - the best ive used so far.....
Materials are excellent - i thing single ripstop with some dacron on the edge - no pullies nothing really to wear out. i run a switch and a liquid force bar with the kites - the 13 mainly with 27 m lines to give it mor dive in light conditions. They are not the most powerfull kites but i feels perfectly balenced and a very good mixture for the hight and low ends....
ive had kites (liquid force 14m) that had a great lowend but stoped at 16 knots! my Gastra 13 goes from 13 knots to about 30 (nice is untill about 22Knots
) lower than that i go sup boarding or mountain biking to give me stamina for more time on the water
I would describe the Pure 2016 (similar to 2017) to be a higher performace alround kite that is great fun and relative easy to fly - quick but not too fast, water start is perfect - short bridles. i can also say its a jumping machine and really does have great pull upwards (thats why i would not recommend the kite for beginners) the 13 with longer lines slows it down and allows more control and time in the air for tricks.
I have no comparison to a switch blade (should also be a good kite) . the bar pressure is in the middle catergory - i like it light for long sessions but the pure seems to hit the point and it has a perfect feel and you always no where the kite is
.
I also had an older gaastra jeykl which was so well made it was bulletproof but also too heavy but in a 9 m that does not really matter. the pure is lighter ( 3 stuts are more than enough) with much less dacron material and seems to be holding up really well my third session has just started with the kites and there are no signs of wear and tear - i do look after my kites....
living in Germany gaastra are becoming popular again and rightly so, they are cheaper than most and are great to ride....with no drops in the qualitat ...
oh yea i weigh 82 kg dry (board 142x42) - so i quess the pure 13 would be good from about 15 knots with twintip for your 100 (real world knots
)
Hope i could help....