For cool days, the FJ Performance Sweater is outstanding! - It's light and doesn't feel like your wearing anything extra, but it keeps you VERY cozy. For windy days, the base layer and windshirts are essential. As for the shirts, I have several of each and can't really tell the difference in feel, just the look. The slacks and shorts are a heavier grade that gets too hot for my tastes in the Texas summer, but are great below 90 degrees.