I used my Wipika Classic for 2 years and had tons of problems with the
bladder. In the end, I bought 2 spare sets of bladder for my Wipika
Classic 5.0 and 8.5 (I currently still have the same bladder problem
with the Wipika Classic 3.5).
I used the AR5 for 2 years now and NEVER have any problem with the
So Naish made the bladders stronger and probably at the same time make
the kite heavier; however, due to the higher aspect ratio, the AR5
performance is still slightly better than the Wipika Classic.
So my AR5 5.5 performance is slightly better than my Wipika Classic 5.0
(which is perfect! :-)
But my Naish 11.5 performance is ONLY slightly better than my Wipika
Classic 8.5 (which is a problem because the Wipika Classic 8.5 is
already too sloooow).
So for a small kite (used in 12 knots and up) it's better to have
stronger bladders such that one don't need to care about them (kite
weight is not an issue here).
And for a bigger kite (used in less than 12 knots), it's may be
desirable to have thinner bladders for higher performance (or no
bladders at all...)
P.S., Unless you have strong bladders such as the AR5, it is recommended
to get a spare set of bladders (the bigger the better as bigger bladders
will work in smaller shells - down to a limit of course).