I may get flamed for this, but as long as they pass the recommended testing protocols i.e. SFI etc, then it comes down to ease of use and comfort. Do not get anything less than 3".
I sell Simpson, and have both Simpson and G-force in my car. The Simpson webbing is better quality, but the user friendliness (is that a word?) of the G-force is better. The G-force has nice wrapped ends that allow you to adjust the belts very easily, where as the Simpsons are a little harder to grab the ends to tighten. Other brands have padded groin pieces and shoulder strap latches to reduce pain and injury in the case of and accident.
I have both cam lock and latch and lock. I was a fan of camlock before a racer friend of mine metioned he has had camlocks come loose and he prefers something that cannot mess up when he needs to get it loose in a hurry.
BTW, the SCCA research association has recommended we change belts every 2-3 years instead of 5 due to changes to web strength and stretch from sunlight and airborne contaminants.
