Joined: 02 Aug 2012
I assume you mean between the PSP daily build from Buildbot and a release build... Well, mainly that the daily build is automatically generated from the latest source code for development branch (master) and release candidate / last release branch (stable). As the notes here indicate:
This means it likely has had no testing and could be broken in various ways and/or crash... It is also likely compiled with debug options so it may run slower than a release build and/or produce debug output.