Are the pliers wrench really that great?
Yes, yes, yes, yes, and one more: yes.
My "must haves":
At least one pair of Cobra-style pliers
"Pliers wrench"
CoBolts (Or one made by similar mfg's)
The pliers wrench is seriously good! I got the 10" and appreciate the sheer versatility. The jaws aren't serrated, instead they're nice and flat. So they don't muck up fittings or anything, and they give a hell of a grip on everything I've tried them on. Even some purely round stuff. Since they're parallel, you can push pins into small parts with them, or help align parts with them as well. And the adjustment range is rather large. Overall a really helpful tool with tons of uses.
It's like an adjustable. Which is exactly what I thought about in the store before I bought 'em. But you gotta use em to know just how much better the adjustable wrench is with a bit of squeeze on the jaws

And they're not nearly as slow to use. Check out knipex's videos on the wrench where they show the action of the wrench when you're turning a nut. You get to keep the wrench on the fastener without pulling it the whole way off. Awesome for larger sized stuff.'
edit: Monte of all people is a person whose opinion on this subject is especially accurate! And he's got the videos to prove it
