Having to rely on the correct version of PIAs to be deployed for implementing Office add-ins has become the inevitable reality for many Office devs. This reality is quite gruesome, I must add.
Andrew Whitechapel describes a technique allowing single add-in to target both Office 2003 and Office 2007 by importing interop definitions that are new in Office 2007 PIAs directly into your assembly. This allows you to use Office 2007 features w/o depending on Office 2007 PIAs. It is a good start to become PIA free.
Tell me your story. What has been your experience with PIAs and limitations that those impose on you?