BEFORE YOU BUY PYREX, read this....
Did You Know There Is an Actual Difference Between PYREX and pyrex?
Are "PYREX" and "pyrex" the Same?
Both trademarks were historically used interchangeably in the marketing of kitchenware products made up of both borosilicate and soda-lime glass. However, now Corning has licensed out the use of their PYREX (upper case lettering) and pyrex (lower case lettering) logos to other companies.
Lowercase pyrex is now mostly used for kitchenware sold in the United States, South America, and Asia. In Europe, Africa, and the Middle East, uppercase PYREX is still available.
Pyrex eventually switched to tempered glass most likely because boron is toxic and expensive to dispose of. Although tempered glass can better withstand thermal shock than regular soda-lime glass can, it's not as resilient as borosilicate. This is what causes the shattering reaction people are talking about.
If the logo is in upper case lettering, PYREX, it's most likely made of borosilicate, and thus safer. The lowercase lettering is most likely made of soda-lime glass, so take extra care after any high-heat cooking. Most glassware products will include warnings so make sure to read about proper handling, cleaning, and storage.