I have been summoned!
Folder vs. Fixed Blade
Aside from folders being cool mechanisms, the only time a folder "wins" is if you don't have the choice to carry the fixed blade, whether because of law, size constraints, sometimes a safety issue. etc. As mentioned, fixed blade is always stronger and almost always faster to deploy and always simpler to deploy.
If you might absolutely need your knife to save a life in a hurry, I think a fixed blade is the only way to go. Any folder can be fumbled when trying to open it. If you are in a compromised position (in a car wreck, some miscreant trying to pull your limbs off of your body, your hands are too cold, etc.), you don't want to have to worry about opening a folder, no matter how reliable it is.
In terms of carry, neck carry is super easy and super concealable. Comfort is a very subjective thing, but it's something you can train yourself to tolerate. You should be wearing an undershirt anyway, so the neck knife between undershirt and outer garment is usually not a problem. The potential downside of neck carry is that it may not be in exactly the same place and orientation all the time (again, if you're upside down, or someone is wrestling with you, or you're in the water, whatever). That's where belt carry shines, especially near the centerline of your body where you can access with either hand.
On the other hand, with a neck knife, you don't need to be wearing anything else to always have your knife with you. It sounds silly, but sometimes weird things happen.
I started carrying a neck knife (almost always a fixed blade, but I have worn folders that way too) after I was in a situation where I needed my knife, but I couldn't reach it on my side (bwframe probably knows the story!). If I were carrying "a knife" primarily as a defensive tool, they would be fixed blades and both would be inside my belt line on either side of my belt buckle (imagine a crazed pachyderm, dual wielding fixed blade karambits with each of his T-Rex arms. Now try to sleep tonight).
If you're going to carry a knife specifically to use as a defensive weapon, then fixed blade wins.
If you're carrying a knife for other emergency use, then the fixed blade wins.
Folders are to fixed blades as handguns are to long guns. The former is a compromise for convenience, whereas the latter is generally the better tool for the job.
So final answer: carry both.
Folder vs. Fixed Blade
Aside from folders being cool mechanisms, the only time a folder "wins" is if you don't have the choice to carry the fixed blade, whether because of law, size constraints, sometimes a safety issue. etc. As mentioned, fixed blade is always stronger and almost always faster to deploy and always simpler to deploy.
If you might absolutely need your knife to save a life in a hurry, I think a fixed blade is the only way to go. Any folder can be fumbled when trying to open it. If you are in a compromised position (in a car wreck, some miscreant trying to pull your limbs off of your body, your hands are too cold, etc.), you don't want to have to worry about opening a folder, no matter how reliable it is.
In terms of carry, neck carry is super easy and super concealable. Comfort is a very subjective thing, but it's something you can train yourself to tolerate. You should be wearing an undershirt anyway, so the neck knife between undershirt and outer garment is usually not a problem. The potential downside of neck carry is that it may not be in exactly the same place and orientation all the time (again, if you're upside down, or someone is wrestling with you, or you're in the water, whatever). That's where belt carry shines, especially near the centerline of your body where you can access with either hand.
On the other hand, with a neck knife, you don't need to be wearing anything else to always have your knife with you. It sounds silly, but sometimes weird things happen.
I started carrying a neck knife (almost always a fixed blade, but I have worn folders that way too) after I was in a situation where I needed my knife, but I couldn't reach it on my side (bwframe probably knows the story!). If I were carrying "a knife" primarily as a defensive tool, they would be fixed blades and both would be inside my belt line on either side of my belt buckle (imagine a crazed pachyderm, dual wielding fixed blade karambits with each of his T-Rex arms. Now try to sleep tonight).
If you're going to carry a knife specifically to use as a defensive weapon, then fixed blade wins.
If you're carrying a knife for other emergency use, then the fixed blade wins.
Folders are to fixed blades as handguns are to long guns. The former is a compromise for convenience, whereas the latter is generally the better tool for the job.
So final answer: carry both.