If you are managing a large website make sure to check out this new tool from Google.
I am using the Tag Manager on my own website and some of the sites of my clients. I have found it easy to use and allows for the ability to grow as Google changes. I really like the ability to add new code without having to wait for a third party webmaster to get around to scheduling time for the code addition.
The only area of difficulty that I have seen from using Tag Manager, is the confusion some webmasters have on the publishing function. Some will set up the tags properly but forget to publish the Tag Container to the site again.
Make sure to watch the video as it will take you through setting up AdWords conversion tracking as well as Google Analytics code installation. With remarketing becoming popular for many AdWords accounts, having the Tag Manager in place on the website allows you the account manager to set up remarketing by just updating the container from within the Tag Manager control panel.