loosing a $150 rod, reel, line, diver, flasher, fly combo, on a plastic holder is not a good thing.
A few years back I was fishing on a friends boat, who had plastic diver holders. We where using my diver rods, and yes a King hit and SNAP!. luckily I was standing next to it and made a quick grab. you can get Big Jon holders for around $50 each. I got mine at MC Sports here in GR. for that.
Big Jon IMO makes the best of the lesser expensive holders. Easy to use and strong enough for the average weekend warrior. I started with Tight Locks, but had them strip out when big Kings hit.
This is the one I'm talking about.