Pros: Easy to use. Highly versatile! Looks sweet!
Cons: Some of the gestures are not consistant. Not pressure sensitve
One of the things I'v e learned in the Apple store is 'look, but don't touch'. I know, I know that they actually encourage you to touch and touch a lot. The thing is once you touch it, you've got to have it and if there was ever a device you should keep your fingers off of, its this one. Once you run your fingers across this brushed aluminum slab, it is all over with. One finger, two fingers, three fingers, four! Pinch, swipe, back and forth, left to right, up and down!. Yes, it is technical porn. I don't even have a mouse anymore. Just my wired keyboard and this wireless wonder.
What gets me is that it looks so minimal and yet it is so highly functional in the Apple kind of way. In the same way the iPhone has wrecked me for other phones (more than one button now frightens and confuses me), the Apple Magic Trackpad has wrecked me for mice (mouses?). I love that it sits where it sits and you don't have to worry about running out of real estate like you can with a mouse I also like the size of it compared to the size of a trackpad on a laptop.
The only thing I don't care for is that sometimes it gets kinda jerky and that can be annoying and I don't know of a quick fix for that, not even a restart. Also it would be nice if the battery strength was more easily available in the menu bar like the Airplay menu.

I personally have a GeekTool geeklet that sits on my desktop http://projects.tynsoe.org/en/geektool/
Here's a pic: https://dl.dropbox.com/u/274092/CalepinPix/trackpad-battery-level-screengrab.jpg
I forget where I found the code for it, somewhere in the geeklet ecosystem.
I believe the business part of the track pad is actually Glass.
'tsall good though. +1's for all of the other comments on functionality and mouse
obsoleting.
I think Apple's approach to the "touch screen computer interface" is much better than Windows just for the fact it keeps me from slathering my computer screens with fingerprints. yuck.
Two things I don't want to do: view my work through a mass of finger gunk and continually clean my computer screens.
And options - particularly options that don't cause you to lose any existing ways of doing things or require even the slightest learning curve (i.e., they just work and are, as Apple's been reminding us for decades, "intuitive" - are, you know, good things for users.... ...not to mention that iOS devices have totally trained us to just want to "reach out touch" things we can see...
....Apple IS going to end up copying Windows on this one, or lose at least an increasing number of incremental sales over the longer term....
And options - particularly options that don't cause you to lose any existing ways of doing things or require even the slightest learning curve (i.e., they just work and are, as Apple's been reminding us for decades, "intuitive") - are, you know, good things for users....
...not to mention that iOS devices have totally trained us to just want to "reach out touch" things we can see...
Apple IS going to end up copying Windows on this one, or lose at least an increasing number of incremental sales over the longer term....
And, no, I have no standing in the pundit biz', just a forum poster, and I'm not a pro, and I'm saying we'll see this happen within two years - give or take 6 months.
Obvious early applications are like the one in the MS ad showing a kid drawing on her screen and one can imagine a later Photoshop where direct screen manipulation would be a boon. And moving elements around on Keynote slides would be great for me.
Every mouse and trackpad gesture and every menu choice and keystroke combo could be retained indefinitely.