i go with al.ball-lox on lifeline and steel screwgates on rigging.
i rig everything with biner/sling sets, i use biner/slings as a component-universal adjustable hitch, and quick connect/lock. Such as for handles, bending lines away from each other, bending lines for more friction, less friction, false crotches (pulleys and frictional), redirects, gravity bending (speedlines), footholds, sliding or fixed handholds, preset hitches while waiting for line to return, 3rd-balancing personal hitch, extension, cowhitch, drinkholder, tool delivery, tool hanging, bundling several limbs in one load, adjustable anchor point, remote release, line guide, extra supports, securing deadwood on removal limb (so it doesn't come off on lowering/gravity bending) etc.
Very versataile hitching system, spin lox seem easy for groundies to open with gloves and return. If you have enuff, they just undo biners from rope eye and return line with the previous runs biner/slings. Then line is drawn up to waiting hitches, as ground control is undoing the present slings. This also gives me more time to consider exact placement of hitches for various effects, moving and second guessing them. Also, i use them enuf to think enuf moves ahead to use the same sling and position several times for several things before removing it.
Some problematic things, like a crotch hooking a limb when being lowered can be disarmed easily with these. Or if the head gets hung up on lowering you can cut limbs and load with slings on the butt end, if line is tight, this can lighten and free the head by lifting it out.
i bought them for gravity bending, only used them if i had the time to have them sent up, then just started to carry them up, cuz i knew that was the only way i was going to get to try all the uses i was thinking of. Learning curve jumped in many ways.