i think EP is pretty easy and a great way to do it if you are looking at a few hundred dropship products, but if you are doing a few thousand you might want to give inventory source a try.If you want the dropship data feeds automated Inventory Source.com is able to upload the dropship products and images from the suppliers and update the product details for u.
U can use the supplier data feeds and easy populate to manually update the products. However, as the feeds get very large from some of the big suppliers, the uploads seem to take VERY long and sometimes time out. I know you can split the files, etc....but the IS zen cart loading and updates work without needing to upload the files through EP and they update the products right on the database.
http://www.squidoo.com/zencartdropship