If you are managing hundreds of AdWords campaigns it would be tough to maintain as you would always need an overview of reports of each client. Though AdWords provides - Overview (@ My Client center) of all the accounts associated , sometimes data provided is not enough to deal with.
After Adwords launched its API , there are many companies mainly Internet Marketing companies have pop'd up with AdWords reporting tools

. Here are few of the Plugins that you can add for your Excel to automate reporting..
Among this - Google AdWords API Extension by SEO Gadget is free that you could have a try, Tatvic , surprisingly an Indian Company, offers a 20 day trial too.
