Makrolon and EZ2CY are rigid alternatives to eisenglass, and Regalite and Stratoglass are flexible alternatives.
We have the new Makrolon Marine 5 for our front three panels, extra UV protection, slightly flexible (as we pin one panel to the hardtop), etc. The original Makrolon we had was installed in 2009, started to yellow in late 2017, went further south in 2018, replaced earlier this last Spring.
Our other 7 panels are Regalite, .040" gauge I think, with roll-up "smiley's" for ventilation. Seems better than the original Stratoglass that came on the boat. Panels installed in 2009, one replaced because of an owner malfunction that caused a tear... otherwise all good. That said, we usually dismount and store the 5 aft panels during the Summer.
Otherwise, the front 3 Makrolon and 2 Regalite panels are up 24/7/365...
Everything sewn into Sunbrella, with Tenara thread. Coil zippers on the smiley's.
-Chris
-Chris