I like how Seller Tools has saved me time! Before, I never posted things to Twitter, Facebook, or Flickr, because I just didn't have the extra time! Since using Seller Tools, I have seen traffic to my store double, if not triple!
Seller Tools is very user friendly. I like that it gives you all the information you need to improve your Etsy shop. It also gives you hints on keywords to use that help you sell your merchandise.