The problem is twofold. Unlike a lot of software that you can simply install right over the old one, I really don't think it is a good idea to try that with AC. Not only that, you must install it on every client, and I tend to uninstall and install there as well.
Couple that with the fact that you are playing with probably the most important data you have. Maybe your billing is comparable. This is probably the biggest reason I don't update every time one comes out. I tend to wait even with an official release to make sure it isn't buggy. I couldn't imagine installing v6 only to find out it isn't consistent with the Star Printer. I would then have to revert back to a version that was. So, then I would have to wait on the beta "patch" as well.
