I have been blogging on my WordPress site for some time and using Zemanta on it for a while. What a joy it is to find that it is available on my Blogger blog as well.
It's hands down the best tool to get help in a blog and add value to your blog - well quoted and giving proper credit to the elements, images and text you use. I can recommend this.
If you know of any draw backs to using Zemanta then please leave a comment on this blog...
I'm using Chrome for my blogging and some offline software as well, but I can recommend the plugins, both in Chrome and in Firefox.