WordPress is free to download, and Google Sites is already there on the web for you if you've signed up for a free Gmail account. There's an embarrassment of riches out there for anyone interested in creating a web presence for little or no money. But there are always hidden costs to anything that's "free", and if you want to put an organization or business online on a low budget it's good to know them now. Here are some of the most common criteria. I am discounting sites hosted on WordPress.com because they can not take advantage of the most compelling WordPress features, such as plugins.
Easy to get started
We all have too much to do and too little time, so ease of getting started is important. Google Sites wins this hands down because it requires no installation or download step. WordPress, on the other hand, must be obtained from the WordPress site and you must already have a web hosting account in order to make use of it. Winner: Google Sites
Easy to maintain
At first Google Sites looks easier to maintain. For a very small site, it may be. But the WordPress internal architecture lets you create a dramatic appearance differently simply by changing or manipulating a theme. WordPress themes are infinitely richer than those offered by Google Sites. Thousand of gorgeous WordPress themes are available free all over the web. Winner: WordPress
Ability to add features the product does not yet have (extensibility)
No software product, ever, has fulfilled all its users' needs. The best ones have an extensible architecture: Photoshop, Microsoft Word, Excel … and WordPress. Want to add affiliate sales through Amazon to your site but have no tech knowledge? No problem, there's a WordPress plugin. Want to sell your crafts, artwork or services on your site? Plenty of WordPress plugins for ecommerce. Want to do any of those things from a Google Site? Sorry, no can do. They do not have an extensible architecture. Winner: WordPress
Third party support and training
All successful software products have lots of consultants, books, and training programs available for them. That means if you end up not having the time or technical knowledge to add a particular feature to your site, you can rely on a web ecosystem to find the help you need. WordPress has well over a million installations, tens of thousands of knowledgeable developers, and lots of books available both online (for example, http://www.OnTheWebInAnHour.com ) and offline (your local bookstore). Sites? Not so much. Winner: WordPress
Easy to move to another host
Do you like being tied down to a single company for anything? Most people who have responsibilities in any business or organization understand that's not an acceptable risk. One policy change, one simple decision to move into your previously undisturbed market segment, one rep who just does not like you, and boom! Your comfortable niche is gone. Or what if you just have liability problems, or find a better deal elsewhere? Moving a website can be traumatizing enough. Make sure you can do so easily. Moving WordPress sites is child's play; HostGator, for example, will move it for free. What makes Google Sites so wonderfully easy to start under the hood results in a site full of all kinds of extra, copyrighted Google code you can not take with you. Plus they just do not have a good mechanism to allow you to take all your work with you to another host. It's a big gotcha. Winner: WordPress
Building a website is easy now. The ability to update articles yourself, keeping it running, getting third party help, and having a choice of web hosts make the decision far more different than you might have considered.