I like the keyword tool, It really puts things in perspective. I love the ability to see what is the most popular in my shop via views and purchases. The sort function is awesome! I just clicked on the analytics reporting page for the first time today and it seems like there is a lot of meaty information there!
I tested it by using it, then not using it. The "not" using it was hard. I found it much easier to schedule the posts, then forget about them. I did wish that I could have put more specific information for Etsy teams on Twitter so they would be caught by them better. but the pictures worked extremely well. I found I expanded my target audience using the system, and sold more, which is the bottom line.
What is the most useful for me is that I can schedule posts for my shop throughout the day. Even if I was sitting at my computer all day long, I wouldn't be able to keep posting for different time zones worldwide.