Polycarbonate faces

I am a fan of always using poly, my guys are far to rough while trimcapping/refitting faces after install to go with acrylic. About the only time I put acrylic faces on a channel letter is when I'm doing red letters... or when I'm doing a face fab job for Lowes, they spec impact modified acrylic. Those are never fun.

 

Yup, on red letter faces with red leds is about as bright as can be.
As far as cost goes, they look to be very similar as far as pricing is concerned. The lexan is, in a way, more difficult to work with, but also more forgiving. Dropped letters don't break, and since it is a roll product I can specify the length of a sheet, where chemcast is pretty much one or two sizes only from my distributor. But since it's a roll product it tends to have a warp to it, so when trim capping it is important to make certain the lexan is flattened out before gluing, sometimes requiring weights around the letter while the glue dries. Also this can be an issue when cutting, as the more that gets cut out of the sheet, the more it wants to lift. I started ordering from my distributor in cut to size sheets that work for my application, so it tends to lose some of the roll tendency as it gets transported. Also you need to make sure whatever adhesive you are using actually works, not just that it says it will work... We use channelbond for all trimcapping. I just realized you're in Texas, so I'd recommend calling up Reece Supply out of Irving. Great folks, and they always go the extra mile in replacing in type of damaged or defective products.