For chrome, I like using the "REST Console" extension (https://chrome.google.com/webstore/detail/cokgbflfommojglbmb...), which I believe has all of the benefits you listed. The "credentials stored in a browser" thing is the main reason for me to be using it.
For Firefox I recommend Poster: https://addons.mozilla.org/en-US/firefox/addon/poster/
* Better security for the user (the paranoid in me do not want to send my credentials through a third party site).
* It could use the credentials stored in the browser (cookies, basic-auth, etc).
* The IP of the requester would not be hidden, allowing IP filtering for development servers.
* It could run on a PC that is not connected to internet.