[GreenSock]

With over 1.6 million sites using GreenSock (and growing fast), I'd say it's gotten plenty of love outside Advertising/Marketing circles ;)

It's widely seen as the go-to animation library on the web...period. Most award-winning sites use it. Chris Gannon is clearly a magician with it. Love his work.

As for the licensing, the codebase is on github and it's free to use in the vast majority of use cases including most commercial ones. See http://greensock.com/why-license/ to understand the "why" behind the model. Hopefully you'll see how it can actually be a very good thing for the community (as evidenced by the decade-plus track record and ongoing updates). But I realize it's not for everyone and that's okay. There are some misunderstandings out there about the license, so I hope folks will take a moment to read that article I mentioned above.

Happy tweening!