SP1 contains a significant number of breaking changes. It is much more like a new version than a service pack. I would expect bug fixes and non-breaking enhancements to be in a service pack.
- The "upgrade" to TBB 4.2 causes me compiler errors
- The "upgrade" to IPP 8.0 contains a new library file layout, forcing me to rewrite my build scripts
- An entire compiler suite (MSVC 2008) was deprecated
- The software update manager was installed automatically