I like the finger tab hooks mainly as I think they are made with stronger steel. I find the standard ones get bent easily if they stick out below the fins. The finger tab ones are usually easier to use as well.
I like the finger part, for easier removal, but does sometimes gets in the way of igniter insertion, igniter leads, and I do believe it'll have a slight sway on the motor exhaust. Also, the finger hook part can be used to hang your rockets from a string suspended between two walls. (I did this in one place I lived, so they wouldn't get lost on the floor, ran a string and hung them up by their hook!)
I like the standard because of the clean look and no interferences, but they can be a bit of a pain (literally - like them catching under your finger nail!) when removing motors..
I like the finger tab one. As stated above easier to work and never encountered a problem. However, last night I constructed a motor mount for a 2 engine cluster for my next Big Bertha. The mount came with 2 standard hooks, but I used 2 hooks with the finger tabs. I did this with OUT putting any thought into the ignitor/wire/clips and their interaction with the finger tab. I can see I will have to be careful when setting up on the pad.
I *generally* like the finger tabs because they're just easier to manipulate but there are times when the design of the rocket/motor mount just make them impractical so I make, and keep stocks of both kinds.
The finger-tab ones are easier to use (I like the idea of hanging the rockets from a string, too - thanks) but sometimes they can get hung up on the clothes pins we have used as stops on our launch rods. We're trying to use spent motor casings to keep the rockets off of the blast deflectors but some designs need the extra help.
Both, and none. It depends upon the rocket. I've had rockets that I built specifically for landing at "The Rock" (large asphalt parking lot) that have the motor mount up inside a fg-reenforced aft body tube. The tab on the hook gives extra leverage when trying to move it out of the way to pull a spent engine. Would not want the extra "stuff" on a minimum diameter rocket
I have to say though that I was glad that I didn't cut off the finger tab when it came to my Mercury Atlas rockets. The finger tab allowed me to straighten them out and extend the engine hook to the current length of the E motors, instead of the shorter (short lived) versions that were introduced at the same time as the Mercury Atlas kits were released.