I just went on my first long ride in the new Alpinestars 365 Gore-Tex Leather Suit. It was dry and sunny, so I can't tell you how well it keeps out water, but I can tell you the perforations aren't there to vent air. So what do they do? Allow the Gore-Tex membrane laminated to the underside of the leather to vent water vapor.
Expecting all the tiny holes to flow air like a wind tunnel, I put on a
sweater when I set off in the 50-degree dawn temperatures, but it turns
out riding in the suit is just like wearing non-ventilated leather. At
75 degrees, having long since ditched the sweater, I had to unzip the
jacket halfway to stay cool.
Gore-Tex Pro Shell Leather is treated with a dye capable of reflecting
30 percent of the sun's energy, allegedly keeping you cooler than if you
were wearing standard black leather. Without trying this and a standard
suit back-to-back, I can't comment on the dye's effectiveness.
On initial impressions, it feels like the suit's going to be a bit too
hot to wear in the heat of the summer, at least at relatively mild
speeds. Perhaps eVent would make a better membrane for a true
all-weather a motorcycle suit.
I'll keep you updated.