Part of what makes UserBugReport special is automatic diagnostics. This saves your users from lots of data entry, and saves you from playing 20 questions.
Since a picture is worth a lot, our core metadata is a screenshot, with the ability to place callout annotations. You users will be shown a screenshot of your page when submitting the bug, can click on any location to drop a pin, and leave a comment with that pin.
The URL, headers, browser information, date, time, locale -- are all extracted automatically and included in your bug report as structured, formatted JSON that you can read by human or machine.
You can even include your own data, which will be sent along with your bug report.
window.userbugreport will be picked up and sent along encoded in JSON when a user reports a bug.
We capture the console for you and attach that to the bug report. This is extremely handy to know all the errors and messages going on. Think of all the times you asked a user to open up the debug tools and reproduce an issue. This is that -- but automagic!
Web pages talk to the network, and knowing what was pulled by URL and how long it took comes in really handy in diagnosing partially broken pages.