My machine at work upgraded to SP3 (my home one already had, without apparent issues), and Adobe Framemaker 7.1 (not the latest version of the software) stopped working. Like, at all. It's now unsupported by Adobe, so my only option was to roll back to SP2.
Also, we use the "Address Toolbar" regularly at work on our machines. SP3 - for whatever sad rationalisation Microsoft feels it needs to come up with - removes this toolbar as an option. There are workarounds (involving replacig a .dll with an SP2 version), but it's an unexpected pain.
Apart from those issues though, I've not noticed anything major. Yet.
Also, we use the "Address Toolbar" regularly at work on our machines. SP3 - for whatever sad rationalisation Microsoft feels it needs to come up with - removes this toolbar as an option. There are workarounds (involving replacig a .dll with an SP2 version), but it's an unexpected pain.
Apart from those issues though, I've not noticed anything major. Yet.