Hi there,

I am new to the POD environment, started in the later part of last year.

So far, I have accounts at Zazzle, Cafepress and Spreadshirt. I am concentrating on Zazzle at the moment as it is the only place I have sales. Will want to give more time to the other two when possible.

My humble opinion of the 3 sites are as follows:

Zazzle:
+1. Supportive and active community where Zazzlers provide useful information in the forums to help newbies.
+2. A good range of products.
+3. Zazzle's tie ups with other partners like Groupon for promotional activity.
+4. Volume bonuses the more you sell.

-1. Design phase do have hiccups or experience slowness.

CafePress:
+1. Place the design immediately on many products and one has a sensing of how the design looks. The other two sites, you will need to set up templates.
+2. A good range of products.
+3. Established the earliest.

-1. Low royalty fixed at 8%. For the other time, you can determine the royalty amount. 
-2. Design interface does not allow you to move or remove the design on certain products. The black pillow is one that shows the design in a bad white cause it cannot set the white as transparent.
-3. Need to pay a fee to get better perks for starting shops.

Spreadshirt:
+1. Most user friendly and dynamic design interface. One can even add designs and text on the sleeves.
+2. More personalisation options available for customers. For example, customers can choose among several design templates uploaded by different designers and mix and match and change the colors to their own preference. 

-1. Limited range of designs.
-2. Spreadshirt UK and US search engines and shops are not interconnected. You will need to set up shops on both domains.

So my order of preference is Zazzle > Spreadshirt > Cafepress. But I do hear people have more success with Cafepress than Spreadshirt.

Hope this helps!