Most of the [examples](https://github.com/mbostock/d3/wiki/Gallery) provided are by the author, but there's also a great community writing plugins and more examples.
Ranked in these QuestionsQuestion Ranking
Pro Huge number of examples online
Most of the examples provided are by the author, but there's also a great community writing plugins and more examples.
Pro Large community
D3.js is a very popular tool with an active community, resulting in plenty of learning resources and fast responses to questions.
Pro Doesn't require a proprietary framework
D3's emphasis on web standards gives you the full capabilities of modern browsers without tying yourself to a proprietary framework.
Pro Versatile library for manipulating data on the DOM
Pro Very flexible join paradigm
Can be tricky at first, but once learned, data manipulation and binding can easily generate complex visualizations for massive amounts of data.
Pro Great for highly interactive scenes
D3.js offers incredible levels of interactivity.
Pro Backwards compatible
D3.js is intended for modern browsers, so supports IE9 and above (IE8 with an additional library) as well as all the other modern browsers.
Pro Few dependencies
The only dependency Animo has is jQuery. The source also includes animate.css as a stylesheet, but you can always add yours if you wish to do so.
Pro You can get personal help from the development team by paying
The animo.js team offer the option to contact and get help personally from the dev team by paying an amount of money (2 days for $5 2 weeks for $30 Lifetime for $100).
Alternatively, being an open source project you can still open an issue and get help from other developers that use this library.
Pro Includes CSS animation library out of the box
Animo.js has a CSS animation library (animate.css) included by default, which provides developers with 60 pre-made CSS animations where they can choose from.
Pro Open source
Animo.js is a free and open source tool.
Con Steep learning curve
The complexity and flexibility of D3.js results in it being a time-consuming tool to learn for many users.
Con "Selections" are elegant, but somewhat hard to grok
Selections are core to working with D3 beyond the basics. They're powerful and useful, but require new developers to get up to speed (e.g. set aside 30m to read and digest: https://github.com/mbostock/d3/wiki/Selections) and if used in the context of a larger application will result in a portion of the code using different patterns than the rest, requiring a translation layer in between.
Con Development seems slow
From their Github repo it seems that development is going pretty slow. Issue reports are still getting answered but the latest commit to the master branch happened more than 6 months ago.