Hey, as the creator of the Node.js unirest library I'd like to say that I love the request library in node. It is indeed fantastic, and constantly updated. That's why I chose it as the underlying framework for the Unirest Node.js library and thought an easier interface for using it would help out. Features like supporting gzip requests, parsing cookies, etc... and the coding style of Java / SuperAgent was the inspiration for it's syntax.
To answer your question aside from the additional features, I think each one is specifically written for the language, built on-top of existing frameworks to bring a easier interface... and what I have personally found developing technologies using this (the site actually uses Unirest Node.js to generate the source, and on our website we use this to show snippets in multiple languages without a drastically different syntax) is the ease of going from one language to the next without having to think too much, and a good pool of documentation in-case you get stuck.
To answer your question aside from the additional features, I think each one is specifically written for the language, built on-top of existing frameworks to bring a easier interface... and what I have personally found developing technologies using this (the site actually uses Unirest Node.js to generate the source, and on our website we use this to show snippets in multiple languages without a drastically different syntax) is the ease of going from one language to the next without having to think too much, and a good pool of documentation in-case you get stuck.