Hey, I have those purple Pyrex also. I have an 8x8 square and a 9x13. I've used them a zillion times and never had problems with sticking or problems with the glass.
I also have some of the older Pyrex which is great!
I also have some Corning Ware French White and French Black. These are simply beautiful pieces that will last forever and ever. BUT, and it's a BIG but, one needs to find the older pieces made in the US of their proprietary material, Pyroceram. It's easy to still find brand new pieces of the older stuff. I've purchased some of mine on ebay. At one point, I dropped and broke one of my original French White pieces. I was really bummed. My husband, sensing this, went out and got me a whole new set.
Well, the bummer was that (and he didn't know this, nor did I ever tell him) those were the new 'Made in China Stoneware' version. I ended up replacing those with all Pyroceram pieces.
This is my idea of beautiful, classy bakeware. I just don't care for busy designs so that's just my preference. I also prefer quality and, unfortunately, this Chinese line from QVC is not made well nor is it fired properly.
Another thing with glassware/ceramics/stoneware is to not take it instantly to temperature extremes. I have always put mine from room temp or cold into a preheated oven without problems. But taking them out of the oven don't put them on a cold, hard surface.
I find that silicone trivets are the absolute best! They aren't hard and they don't cause a temp change that will stress out these materials. I do this with all of my Pyrex, Corning Ware, and whatever glass-type bakers i use.