Thanks for the advice. So far I've had no durability issues, but as I said before, it's all short term experience.
Next time I pick up supplies, I think I'll get an awl and some waxed linen to compare with what I've been using. Probably a groover and overstitch wheel, too. If everyone else is using it, then I need to check it out and see how it works for me.
I am much more of a utilitarian than an artist, and do not mean to offend any sensibilities here. Most of what I've made and will be making is for use and not for show, so my main concern is sturdiness and longevity. The vast majority of what I've been asked to make is for left-handed people and for less common guns.
Leather was easier for me to get into as a medium, so that's why I went with it. A.S. is what looked the strongest, and it was what the local hobby store had. I just never tried anything else.
Does anyone have any experience with long term durability on A.S.? Does it hold up? I don't want to put products out there that fail, so please let me know.