Well, I've finally relented and installed Windows 8.1 on one machine in the house. Frankly, I'm not in a big hurry to do it on the other two PC's I use, including my main development machine. First of all, if you are planning on upgrading to Windows 8.1, be aware of a couple of things:
1) You cannot upgrade directly from Windows 7 to Windows 8.1. Microsoft has, in their infinite wisdom (at least for now) made that impossible. No, you have to upgrade from Windows 7 to Windows 8 first. Only then can you do ANOTHER upgrade from Windows 8 to Windows 8.1.
2) On my bedroom laptop, which is a very fast HP quad core with 8 gigs of RAM, the total time involved ran into the 3+ hour range. Not fun at all!
3) On Windows 8.1 you will get back your "Start" button and menu, but it won't be what you think you were told. In order to get something that looks like the classic Windows 7 Start Menu and features, you'll need to download something like Classic Shell. This is free, and it really is nice, and highly configurable.
Otherwise, Windows 8.1 has some nice features and seems to be very fast. It also will mount ISO files as a "drive" natively, which is nice if you are a software developer. One last caveat: Before you embark on this little venture, I'd highly recommend running the Windows 8 Upgrade Assistant which can save you a lot of trouble in advance. Happy computing!