BRING ON THE BREEZEYou don't know ventilation until you've experienced the GCS Pro. The uppers are like a screened-in porchtake off the shoe and look straight through it to read your watch, if you wish. But its real worth comes with every stride; on a warm fall day in the Sonoran Desert, I could feel air pumping across my feet. Delightful.Bonus: The best one-yank-and-lock lace-tensioning system I've ever used.Bummer: Airy uppers translate into minimal roll control. Overpronators should look elsewhere.