Abrasion resistance. This is the big one for leather lovers, and it is, on a theoretical basis, a slam dunk for cowhide. Simply put, leather is better at going down the road; in a crash, it will abrade slowly and predictably without gaining a lot of heat. (That's not to say it doesn't get hot, but it is not inherently flammable.) Textiles are at a theoretical disadvantage. At some point—and that point depends on myriad variables, including material strength, garment construction, rider size and weight, the abrasiveness of the, er, crash surface and, most importantly, the speed of the get-off—the leather will protect you better in a sliding crash. That's theory, but how about reality? At street speeds, a textile garment is likely to do just as good a job as leather. Why? Because low-speed crashes usually don't involve a lot of sliding, so the textile garment is less likely to drag along the ground long enough to heat up and melt. (No, the textile will not catch fire, but the nylon threads will melt under extreme conditions.)
Care and feeding. This category favors the textile garment. Leather needs frequent care to prevent it from drying out; regular cleaning and treating are necessary for a long garment life. (Then again, a lot of riders consider leather care in the same light as polishing chrome or waxing the Corvette; it's a labor of love, a chance to be close to a cherished possession. Only you know which side of the fence you're on.) Textiles can be thrown in the washer. Done deal.
Feel and texture. OK, another one for leather. While it's true that a well-worn textile outfit can become as comfortable as old blue jeans, there's just something about leather. What's more, both leather and textiles need some breaking-in time. The advantage of textiles here is that you can accelerate the process by washing them.
Weather protection. Leather is a good insulator, but it's nearly impossible to make it waterproof. With advances such as the Gore-Tex layering system, it's possible to make textiles essentially waterproof. (Why the hedge? Even though Gore-Tex resists water intrusion, it's possible, by messing up the design, to have a coat that may not leak through the skin itself but will get you wet anyway. Once more: The more expensive jackets and suits do a better job here.) If you need all-weather protection, textile is the way to go—or always pack a rain suit.
Wear resistance. In our experience, this is a push. Undeniably, leather takes on a wonderful patina after a pile of miles, but textiles—the good ones, anyway—wear extremely well if kept clean. Allow dirt and road grime to get worked into a textile suit, and you may not get it all the way out. That's partially true of light-colored leathers, but they can often be redyed.
Repairability. No question, leather holds a big advantage here, even if it's mainly because so many companies know how to work with leather. It's been around for so long, and the large leather-jacket makers are so well-versed in repairs, that getting a jacket patched up is not difficult. True enough, you can get your Aerostich repaired, but the simple truth is that it's unwise to spend a lot of money repairing a $200 textile jacket—at that price point, the value, not the material, is the issue.
Weight. Hands down for textiles. Modern fabrics are astoundingly strong, and they provide incredible strength for their weight.