I wont wear mesh or anything synthetic for the same reason. It melts and armor gets torn away easily or does not stay in place. Both times I went down while wearing it at slow to moderate speeds (less than 25mph) I had severe injuries, severe road rash and burns. Very little protection. The other two times I went down at high speeds wearing leather jacket and some armor over my knees. Still had severe injuries and road rash but not as severe and I healed much faster.
I've gone down 3 times at speed (40+), with a mesh jacket, Bohn underarmor shorts, Duluth Trading firehose pants, my Fox Shorty kneepads, leather boots and leather gloves. Popped up after all of them - including tumbles, skids, etc. Gear was thoroughly trashed (everything, including the helmet) but my body was fine - no road rash, no breaks, no skin abrasions.
I really cant stress this enough. If your willing to spend a sizeable amount to look good, spend a little extra and learn how to fall. Go talk to your local martial arts instructor, explain you just want to learn to fall and see if he has the time to teach you some basic techniques for a fee. Many of them will do it for a modest fee. Yes, you will get thrown around but under controlled conditions. Better to learn on a mat than hard concrete.
This was the key. I did Aikido for 4 years, wrestled, and played a little football. I learned how to fall, how to roll, how to bounce around. And I learned to trust my gear. Good mesh jackets (Olympia, Rev'it), quality gloves (I like Coretech) and boots (Bates), and ALWAYS hard kneepads (Fox Launch Shortys are my favorites).
My hands, shoulders, elbows, knees, and head all impacted the ground multiple times, quite hard, as witnessed by the destruction of the protective gear. But I was protected. I trust the gear to do its job, and I know I can "take a fall".
Make sure any gear you have fits you properly! It needs to be TIGHT - so it doesn't move around. Armor that can move is no armor. Immobile on your body is the key. Keep the pads in place and you'll be in a much better situation.