Thanks. I gave it a try. Nice tool. Here are the reasons why I think Wishbox is different:

- Wishbox has a drawing tool. You can draw arrows, circles, rectangles etc., add notes and even crop parts of the screenshot.

- JotForm's form builder provides much more customization options for Wishbox.

- It might be a slowness on my end but Wishbox seems to be much faster. [CORRECTION: WebEngage is now very snappy. It must be a temporary slowness on my end] We have spent a lot of time thinking about speed. We are taking screenshots on elastic load balanced EC2 instances so that we can grow/shrink the instances with the demand.

- Wishbox does not require sign-up and free upto 100 submissions/month. WebEngage seems to be limited to 30 submissions "total". http://webengage.com/pricing [CORRECTION: WebEngage is unlimited for screenshots. The limit is only for Surveys]