First of all it installed easily and worked first time, unlike another well known web site tool which I had major traumas trying to install (on Windows Vista).
Have built a couple of web sites now and am very pleased with the tool. Once you get it set up and used to how it works, you can be quite productive - it has all the features I have needed so far, and they all seem to work well. Building, updating and publishing web sites all works smoothly.
It came with a free video tutorial which I watched and which definitely helped get started. The only slight frustration was that this did not include the lesson about building sites using CSS Layouts, which is now the "recommended" way to do it - so it was slightly frustrating that this key piece was missing. But, this was a taster of the fuller (non Microsoft) video tutorial which you have to pay for, so you can't really blame them for holding back on some good stuff.