I also use it on Windows XP SP2. It can be flakey at times, but in general it works OK. I have to make sure I back-up the database (export) after each set of dive downloads. I had it crash on my once and it corrupted the database. It can be finicky when you are entering additional information (SAC rate,comments). If I've downloaded a series of dives, I can usually enter information on 1 or 2 and then it won't let me type into the available fields on the subsequent dives. I have to close and re-launch the software to finish up the remaining dives.
One thing I also do since I don't 100% trust the software is that I (1) keep an excel log as well with main main info about the dive and (2) print out the dive (dive info and graph) to a PDF for backup.