Hey redline201,
I actually ordered the Fieldsheer Mach4 and it's pretty much a mesh jacket with leather on the shoulder, and elbows. Imagine a football jersey and padding, that's pretty much what it felt like when I wore it. Obviously wasn't expecting that, so I sent it back. I have an A* leather jacket and have been getting used to riding around in it in this heat (I live in NYC). I've been trying to wear light tshirts or drifit stuff to help keep cool like someone suggested. Going 35+ in 85 degrees is not bad, and going 55+ in 90+ weather also.
Hope this helps.