Some of the newer Mesh stuff is pretty good, but as listed above only heavy cordura or leather, with CE armor will actually protect you.
I am currently wearing a mesh Vanson with CE armor in the back, shoulders and elbows. It has cinchable sleeves to help with retaining the location of the armor and is made of a heavy cordura looking mesh, nothing like the more popular, and cheaper, Jap brands. I refuse to ride without some sort of jacket with armor but living in south central Florida it is just to hot for leather in the summer even if vented. We both have the Vanson for summer and I wear a HD brand Cordura in winter and she wears a Leather one, both have full armor and vip out full sleeve liners, but winter only. Also for gloves the HELD summer line is pretty good with perforations and coolmax lining.