They both scratch very, very easily. In fact, just running your windshield wipers on a windshield with a small amount of dust on it would permanently ruin the piece. They don't crack easily, granted -- that's why Lexan and Plexi are used in high-vandalism and/or high impact areas such as hockey arena glass. However, if you take a look at any of these installations, you will see how easily it's scratched. Plexi can be scratched with a fingernail, and Lexan with a key. Just imagine the gouges your windshield would have after an hour of highway driving where your glass is continually pelted by small pebbles. I never thought about the scratch issue,some very good replys about using,plastic windshields,again I was going to do it for the short term reason,but after reading about the cons with using plexiglas or lexan for windshields,I will just stick with good old glass for a windshield,I do have one new windshield hanging around but I had planned to use it for Vin #000570(I cracked the windshield by accident,always pad your windshield if you have a storage area above your stored cars,(the car was covered by a thin car cover)but I will use it for the (red)painted car. Also I have found that you do NOT have to use that expensive oil based crummy windshield adhesive,I replaced a windshield on one of my cars (a GM product) and I used Red Devil Brand Adhesive Sealant called, Lifetime(water based) that is Siliconized Acrylic,(BLACK)and I did that over two years ago and it works like a charm!!The beauty about it is that it is Water Cleanup,so that any residue can be cleaned up without any fuss,and it works just as GOOD or Better that that oil based goop that we call windshield adhesive it has SPEC 230 Performance,AND you can buy it at any Home Depot Store,and it is UNDER $2.00 a tube(10.1 Fl.Oz 300Ml.)I think I used about two or three tubes.Guaranteed to last a life time. Claude 000570