After 27 years of sailing i have come to the conclusion that the Slotted screw head is better than the Phillips screw head ( just incase you wanted to know
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Reasons for this;
> Slotted screw head can be used with any size flat head screw driver, unlike the Phillips screw head if used with incorrect screw driver can burr the head.
> If your stuck without a screw driver the slotted head can be tighten with any flat object eg, 5 or 10 cents piece, key head, unlike the phillips head.
feel free to contribute to my observation
I like Phillips because it is easier to screw in from funny angles.
- Phillips screws stick better to magnetic screwdrivers
- The screwdriver head self centres on a phillips screw, preventing slips
A screw that is missing from your diagram is the hybrid Philips/Flathead that takes both types of screwdrivers!
ultimate screw by the sounds
I would have to say the Allen key head is the best. You would have to try hard to ruin those.
The problem with all this analysis is that it comes down to what the guy in the shop has got in stock that fits your need.
I remember last time trying to buy a few stainless screws for different fins... "we have that one in phillips head, but not that length. We have that one with a hex head, but when you go up to that size you need an allen key head..." blah blah blah...
The best thing about phillips head vent screws is that you can turn them into slotted types with a moments application of a cutting disk in a grinder.
Maybe we should all standardise on the Robertson type?
I like screwing women 
...oh those screws....phillips FTW, but not with to small driver, then you get perma fixed straps like me :(
Hex head bolt is best. Doesnt burr, doesnt break screwdrivers, no pointy driver to stab you if changing fin on the go, lots of material to cut into if needed, good for pulling fins into tight box etc etc
Just taken delivery of a box of hex head bolts - to use with a 10mm ratchet. Cant believe I have not done this before, you can do it quicker when rushing to get on the water (like we all do when rigging, unless you are the sort that chats for two hours while rigging).
The bolt is easier to do up than phillips/flat (the only other two I have used) as you dont need to look where to put it, and can just stick it on, no slipping at all.
