No matter where you stand on this question, there is one thing certain - you will be firmly on three legs...
Tripod design varies in many respects when it comes to the yoke at the top and the centre column, and the doodads that make up the head, but the actual locking of the legs falls into three general categories:
1. Twist lock - where there is a collar around each segment that tightens around the leg as you twist it.
2. Clip lock - where some form of lever flips over and either grips or cams the leg tight.
3. Thumbscrew lock - a t-shaped or round knob tightens a clamp on the leg of the tripod.
The designers scatter these different types throughout their ranges as material and/or general fashion dictates. There is also the business of price - some things are cheaper to manufacture than others and when you are pushing out a tripod for $ 50 you need to watch every penny.
Gitzo have always been the top of the tree when it comes to tripods and I cannot remember seeing anything but twist locks on their legs - this is because they are round-profile legs. The Studex 4 and 5 series have a memorable winged screw for the largest segment.
Manfrotto now favour clip locks but for some time used thumbscrews. Their strong point has been the provision of spare parts - sometimes the ham-fisted manage to break the clips.
Promaster? A mixture as they source from different factories and designers.
Three Legged Thing? Twist. Matches their minds.
Cullmann? Again a mixture, though I must say that the twist lock on my Concept One travel tripod is all I could want - it opens and closes easily and holds a mirror-less camera safely.
Is any of this applicable to what you do? If you are always running and gunning you might need the speed of the clip lock - Manfrotto video tripods are the greatest exponent of this. If you need studio steady you can use the twist lock. Still-life products do not run away.
Mind you, sometimes still-life photographers do, but that is another subject...
