Re: Which knot do you use ???
The hardest test of my knots was made years ago on tributaries to Lake Ontario when King Salmon fishing. I used the Orvis slip type knot to the fly and attached the 25lb tippet to the fly line using a perfection loop.
Every time I was broke off I lost the whole rig (fly, leader, split shot) the perfection loop broke before the Orvis knot. I would humbly submit that the Orvis slip knot is stronger. I use it to this day for all connections of fly to leader and just go a little easier when I have a big fish hooked.
I have very few break off.