As others have stated, pin (and joint for that matter) has no impact on performance. Some cue makers would disagree...
They don't even effect the feel or hit.
Pin makes a difference in a few (nitpicky) areas....
1. Balance. Big pins of the same material weigh more, bringing the balance forward. Although, there are many ways to do this, such as a steel joint, or the choice of woods and the overall design and construction of a cue. But that gets into the realm of customs.
2. Speed. More threads and longer pin - more turns needed to disassemble. Some will ponder at this - but if you've ever played a tournament where there are super short races (to 3 in 9 ball) and the format is moving quickly, and there are run-out players, and the room is such where you can't really leave your cue assembled - then you are moving from table to able often it is very annoying to have to be screwing and unscrewing your cues every 15-20 minutes. One quickly appreciates the uniloc pin.
3. Longevity. Some pins or at least joint designs seem to last longer in that they stay tighter. Others tend to get sloppy and loose. How much this affects alignment, I don't know - but it isn't reassuring.
Some opinions:
5/16x18...this pin is the worst. Bad aesthetics (looks like it should be in jar with nuts, bolts and washers in your garage), doesn't help with balance. Not tight until the surfaces meet.
5/16x14 ...this is ok. Wide compatibility. A lot of great cues and cue makers have used this. My favorite is the Mezz version. Super tight and very precise. Their "united" joint as they call it.
Uniloc ...this is fast. Good for balance too. Downsides ...if not timed right, shafts can come loose during play. If the cue is not very stiff in the shaft or forearm, then the vibrations can cause that pin to rattle inside the insert and it makes this metallic buzzing sound. That said, Uniloc is the most sensitive to proper installation in my opinion. Done right, it is nice. Also, Uniloc is a lot heavier than people think. Because it doesn't stick out far and doesn't look beefy ..but inside the butt it is substantial, and the smooth part of the pin is beefy compared to pins that are threaded the full length.
Radial. I like this. Good for balance. Tight. Although I've seen some loose joints this was likely due to how the shaft was tapped. No cons that I know of. For a big pin, it's one of the quicker ones to assemble. Radial's design doesn't beat up the wood. Probably the best pin these days.
3/8x10. Bigger pin, without the benefits of other big pins like the Radial.
Any of the giant G10 pins...blah. The idea behind these is to not alter the balance of the cue by using metal. They do have a lot of surface area and are often tight. I think they are gimmicky.
Some cues have these oversized large pins that are beyond any functional advantage or balance purpose. They are essentially phallic symbols. Yeah, I said it. And yeah, many of you know it is true.