DVDRW media does not last as long as DVDR but then again you could find greate DVDRW media and poor DVDR media to prove this incorrect.

-> In the end we have the documents and studies from NIST about CD/DVD Care and Handling (see google for those) that help us understand media care and longevity.

The DVDRW erasure cycles vary from 100 to over a 1000 times depending on quality which is very hard to find on the packaging.