if they were all bad, this spanish company would´nt exist any more. It all depends of the specific condition of that one, you´ve got under
your radar. Could be good, could be bad, does´nt matter what name you´ll find on the tubes.
If i would´nt know, were to look after, to check if that rib is ok or not, i would ask someone else who knows, to help me out with that.
I think that Narwahl isn´t made of hypalon, so you really thave to check the tubes, cause you may be have 12 years old PVC in front of you.
If that one was for a long time in the sun...or was stored mostly in the garage makes a big difference.
I am sure there are many out there, who are satisfied with Narwahl, and may be some who have a tin of PVC glue at home to fix little issues