I picked up the vaio, so far so goodI was between a Dell and a small Sony. They happened to come out with the S150 and later the S170 through sonystyle.com. I wanted a lightweight, yet powerful notebook for school and taking around campus. The S170 had impressive specs and a good design. The Dell was released a couple of days after I ordered the Vaio and looks to be very similar. I comes with a less powerful graphics processor, smaller screen, but is a little cheaper.
The Vaio has a nice layout and a thoughtful design. The vaio looks more like a computer and less like a toy in my opinion. I'm sure both are decent computers. The people at Sony were helpful and I had no problems. I like the keyboard feel as well and the built in bluetooth option lets me use the BT500 mouse I picked up.
If having a well rounded computer with good graphics ability is important the vaio has a clear edge. The dell 700M would have no trouble handing the basics and would have a price advantage from what I have read on their website.
I ordered mine from Sony online, but I know Best Buy and Circuit City have the S150 in stock.
Hope this helps