I decided to take the plunge and install Service Pack 2 on one of my machines today. Apart from a fairly large download (266mb) and a very long install time (you’ll need an hour or so) it was entirely problem free.
I have yet to test all of my sfotware but the important stuff (networking, virus scanner, Notes, Domino, WSAD, Office etc) all seem to be running fine. So the question is now, do I upgrade the laptop as well? I think that deserves a couple of hours thought.