No. Lexan windshields are not going to be more durable in most conventional uses. We've used Lexan windshields for a variety of purposes, from reglassing a windshield frame that had been tweaked in a rollover to the point that it wouldn't accept normal glass, to quickly chopped windshields and cheapskate projects when we didn't want to spring for custom glass. Though certainly better than nothing (and actually more durable when doing things like rubbing against rocks), the main limitation we've found with Lexan is that it can break unexpectedly when subjected to high wind loads (18-wheelers passing at speed the opposite direction) and it can craze or splinter in odd situations. Over time it also yellows and becomes more brittle.
We wouldn't recommend a Lexan windshield on anything we were using long-term, or if we did use it, we would expect to replace it fairly often. Still, Lexan is a viable and inexpensive alternative for glass in a variety of circumstances. We just wouldn't use it on anything that sees more road time than trail time.