Hi Guys,
I have seen some dodgy braids and fused products a few years ago here in Australia, though the vast majority in use for GT's etc is far better than the braids a few years ago.
Bear in mind the manufacturer, their reputation, your worth on landing the fish you hook and as already advised, don't skimp money wise on the only thing connecting you to the fish!
The other problem I have seen is in the tying of Bimini's, where during the "compression" of the twists, the angler reefs downwards hard with the tag end...this can cause friction and of course, a very weak spot.
Testing mono years ago, it was interesting to watch people break their IGFA line one to 6 inches in front of the Bimini....every time.
The knot was fine...the creation of the knot can cause problems.
Now, if it's breaking within the first hundred working metres of braid, my theory is the enormous pressure applied with a spin reel and where the line comes off the spool during a screaming run can "burn" the line in places too...hence the reason for heavy drag I use 130lb Varivas....it may end up breaking at 80.
Though if I started with 80, I'd probably be down to 50.....seen enough people pop heavy braid under weak arse conditons to tell me there is more to do with unseen line punishment on "used" line than perhaps what you could see on mono...
If it's breaking at intervals all over the place and is new...it's faulty....simple.
Just my 2 cents worth..
aaron.