Not to drag poor to Jim into this, but I have to be honest, reading several years back, how he mentioned I believe in a review, that using a pot shape, allowed for more nuances.
So at the time, not knowing better, I only looked at, considered this shape, later to realize, it’s about having a big chamber diameter.
So when I mentioned differences between different materials, I really believe if you’re going to test this yourself, you need to test against different materials that all have pretty much the same specs.
Because if you have as an example, a cob with a small chamber diameter, and a briar, with a larger diameter, from my own past experiences, this won’t make for a fair assessment.
I’ve smoked a lot of small chambered pipes, and compared to a larger chamber they have always muted the flavors more, especially on complex blends.
On my cobs and briar pipes I compared blends with, that had similar chamber sizes, I always noticed the cobs delivered a lighter, more airy taste to the blend, which I always attributed to cobs being more porous, delivering this lighter taste.
Performance, as being mentioned before is an interesting choice of words. I consider the performance as to how well the pipe smoked, cool, dry, not gurgling, not wet, just delivering a good smoke.
I even mentioned saying the different materials will perform in different ways, and I have experienced this. Some cooler, some lighter, some richer, some wetter, etc…
To be fair, I would say between all the different materials, as long as they are typically the same specs, the differences might be quite subtle, as long as the quality between the pipes is good.
I wouldn’t say I ever noticed extreme differences, most of the time it was subtle. But with some complex blends, some of the flavors could get lost, and sometimes the flavors weren’t as rich or tasty.