I love working at Microsoft and I especially love getting to work on the operating system. One of the the things I love about working on the OS is that I get to run the operating system as soon as it's built. If there's a new feature, I can have it on my laptop the day it's in the official build (and if I'm really interested in something in particular, even before it's in an official build). I also get to see the evolution of certain features. Something that looked great in a controlled environment with just a couple users might not work as well when it's spread across a division or two2, in those cases (and for many other reasons) you get to see a feature evolve; sometimes minutely, sometimes drastically. You get to see a creation that you have a part in grow up.

There is a downside however. Right now I'm running a recent build and while there are a lot of similarities to Vista, it's not Vista. The OS reports its version differently, the browser is a different version, and other changes that affect my computing experience are close, but not exactly like Vista. Imagine having a key to your car that is close, but not exactly shaped like the key that is meant for your car. There are web sites that just won't work properly and it's often not that they wouldn't work, but the developers were careful and made sure that if they didn't recognize the platform and browser then you were redirected to a polite page that told you that your configuration was not supported. Internally we often have "hacks" to get around such issues so we can test against these sites. application compatibility is key to our success, but it's like that key that doesn't quite fit right; if you jiggle it around for a bit you can usually get it to work, but it's a pain that you have to jiggle it.

The other downside is when I'm trying to help someone that is running "the latest software from Microsoft", usually my parents or siblings. These usually involve talking the relative through something over the phone and I often "follow along" as much as possible on my computer. But now things don't quite match. Microsoft spends a lot of time trying to make things simpler and more straight-forward for users2 and this is goodness, but it also means that my "cheat sheet" (following along on my computer) no longer matches and I get to listen to complicated dialogs being read out a bit at a time while I'm trying to help solve some problem. A while ago I actually got my dad, mom, and sister computers that were identical to my home machine so that I could handle these situations more easily. Now if I could only convince my family to only have computer problems when I'm at home rather than at work!

Overall, the upsides of selfhosting far outweigh the downsides. It can be a bit frustrating now and again, especially when I want to try out the new cool thing "RIGHT NOW!" (today's RN! was Microsoft Live Lab's Photosynth)...but I'd rather be selfhosting than not have the opportunity to do so.

1I also find it interesting why it didn't work when we go to larger scale...quite often it's not that the feature works all that differently for a bunch of users, it's that there are groups of users that use their machines differently or have different hardware or work remotely, etc.
2yes, you can probably provide the counter-example that bugged you, but take a second and think about the last time you needed to enter an IP-mask while setting up a netcard...and I could list many more examples where we have gotten it right