The differences between the two are many, though they are superficially identical. The Google version is less attractive than the Microsoft version. I couldn't figure out a way to get two clocks going, one with local time, and one with Paris time, as I can with Windows Sidebar. Google Desktop, most problematically, is a Web-based install that I would need to manually install and configure on every PC I set up. Windows Sidebar, meanwhile, is installed automatically with Vista, though I of course have to configure the gadgets I want and, in one case, download a third party gadget I find useful (Multi-meter, on the bottom).
Here's the value proposition. Windows Sidebar is better looking, included in the OS I'm already using, and more useful to me. Google Desktop is uglier, needs to be located online and installed, and requires more configuration effort in order to get to a place that is less useful, overall, to me, than Windows Sidebar. Game, set, match: Windows Sidebar wins, and Google Desktop is one less application I'll need to install and configure on each PC.
Now, I'm a tool in my own way, of course, and as public service I will of course download and install the next version of Google Desktop just to see whether it's something I need to think about, recommend, or write up in some fashion. But that's my job. For day-to-day use, for now at least, Google Desktop is history. I'm not thinking about it anymore. (Well, as soon as I finish writing this at least.)
There are so many things like this. I've spent a lot of time fooling around with codecs and codec packages lately, both because I enjoy a lot of digital media content in a variety of increasingly obscure formats. I use and--for now, at least--recommend something called the Combined Community Codec Pack (CCCP), which batch installs support for a slew of audio and video codecs. Nice, right? But I've tried a number of competing alternatives, and it's unclear which is better. More recently, I've come across a wonder media player called GOM Player that not only includes most common codecs out of the proverbial box, but is much more lightweight than Windows Media Player and Apple QuickTime Player. It handles WMV, H.264, and various AVI derivatives with ease. I may replace CCCP entirely, but I'm still testing. So far, it looks like a winner.
My recent conversion to Windows Home Server falls under this simplicity principle. Ditto on my decision to skip out on the Zune: It was just another thing that was really good, yes, but not as good as what I was already using. Why waste effort on something that's not as good? Cell phone, same thing. I was carting around two phones--a 3G, Windows Mobile-based Motorola Q that used Verizon's superior EV-DO network and an iPhone--but since I ended up actually using the iPhone, despite its faults, it seemed silly to pay for and cart around both. (Besides, no one has my iPhone number and now the phone never rings. Another win for simplicity! I'm only kind of kidding.)
You can take this into so many areas. Until a day ago, my iTunes music library had over 4,000 tracks in it, and I have spent much of the past year rating all of the songs in the collection to facilitate easier playlists and so on. Once that work was done, however, it was time to throw out the trash: I deleted all the one- and two-stars songs from the library and from my hard drive for good, dropping the track count to a somewhat less insane 2600 songs. (Next up: The duplicates. How many copies of Van Halen's "Jump!" do I really need?) Culling feels good. Culling is good.
I've also reduced the number of machines in my office--I mean, how many can you really use?--even while I've acquired a few other machines--like an Asus Eee PC and OLPC XO--that I'll review and then jettison if they can't find a useful place in my home. (Which they could, as I have two kids, both of whom have expressed much interest in each.)
What I want to get down to, eventually, is a lean machine of sorts across the board. Less junk in my office. Less stuff to install when I inevitably have to reinstall Windows on my main PCs or on other hardware. Less is more. Maybe Microsoft had a point with its "doing more with less" campaign from a few years back. I'm certainly trying to make it a reality.