It's been a time since I tried to use a new software. Today I tried Windows Live Writer Beta for the first time.
Here are my comments from the first use. After first use, this seems to be a really useful tool for regular bloggers. You are saved from the effort of going to the website and writing your blog over thee. You can simply write the blog from the ease of your desktop and you're done!
The interface is Vista style (like all new Microsoft products), which is a very soothing style. The interface is also easy to use, and it has all the usual options that are found in a normal Rich Text Editor. The best part of the tool is the support of plugins. The tool supports the addition of new plugins, which makes it really powerful and extendable in future. Plugins are available to simplify the tasks like Table creation or source code insertion using a particular color coding.
One thing that I did not find is the ability to add link for the article (you can add links in your article, however, you can not add a link for your article), that is found in blogger. Similarly there may be few more features that are available only in a few particular products.
All in all, I found this to be a nice tool. This may have a few restrictions/limitations for now. However, I guess that this won't take too much time to recover them.