Purify could find memory errors in just a few minutes that would take engineers days or weeks to track down. The dynamic instrumentation capability on existing binaries was huge. The first time I saw it in use was at Sybase. Running a demo version for an hour found enough problems that we instantly sprang for the license.
I used it at Sybase when I interned there in 2009. I've been fascinated by good developer tools ever since. It was such a joy to run, understand the reports and make fixes, and repeat.
