If you want to watch a user journey through your website with commentary, this tool is the perfect one to use, even if it does take quite a few hours for responses. I think if you want to test specific functions, quickly, there are better tools for doing this. Reviewers are very honest and can be quite harsh, so you need to have an open mind to criticism, as what they say is very useful.
WhatUsersDo provides more detailed and opinion based responses. It can take a few hours more than competitors because of this. I would recommend it if you want to know more about the user journey through your website. I would not recommend it if you want quick feedback about a specific feature, image or copy, as there are tools better suited to this.
It has helped us to improve our website copy to see how much users understood about our service and what was memorable about it.
We have changed the information given on certain pages, as we realised users' opinions about our company became more positive after visiting secondary pages. So for example, we moved project examples to the homepage.
We realised that our website did not load properly when using an Internet Explorer browser, so made corrections to this.