Welcome to the forums, Siamese!
You have to remember that Zazzle is different from CafePress in that you don't really setup an easy to promote "store" like at CafePress.
You are creating products that are listed in their main marketplace.
You don't really have a "store URL" that is short or product links that are short (both of which can help you market your site in the search engines).
You also don't get to set your own markup price, you only get a set flat commission per sale on the price they define.
It depends on how you want to market your shirts.
Be sure to weigh all the pros and cons...but yes, Zazzle does have some nice features on their site as well
I especially like their product page is laid out and how you can see the image and garment change when you choose different garment colors (so you can get an idea of how the design will look on different t-shirt styles/colors).
Wow Very Cool 
