I folded down the windshield on my YJ all the time, but it was easy to do. Once I put a full cage in it and removed the upper tie-in all I had to do was remove 2 knobs on the dash side and push it down.
With the JK there is a lot more work and I'm not sure I'll ever do it on a regular basis. Still, wheeling with the windshield down is great. The extra airflow is a very nice thing to have. I'll probably do it from time to time just because I can, and just to justify Jeep keeping it possible.
Americans can sleep peaceably at night because US Soldiers stand ready to fight on their behalf
2008 Unlimited Rubicon: 37's, 3" Synergy Springs, Artec trusses, 5.38's, Winch, PSC/Poly Cage, Bumpers, TNT Alum belly skids, and other doodads