Review on FineUploader by Victor Ceja

I like that it works with any server side language (PHP/ASP) or client side JS framework such as AngularJS without having to write custom code for each one of them.

It's free too! That said there are some things we would love to see in future releases but they seem reasonable considering their popularity. We're using this service mainly for our mobile apps so speed really matters here. The ability to use multiple languages at once has been extremely helpful when working remotely from different countries.