They have a live demo and more information on their website
Ranked in these QuestionsQuestion Ranking
Pro Very expandable with a well implemented API
Pro Interface and interactions are clean and robust
Play with the editor to prove it for yourself and see all the testimonials here.
Pro Very lean
Pro Excellent sanitisation of word and HTML pastes
Go to the editor and test the automatic sanitisation of word/html inputs.
Pro Supports Drag and Drop file/image uploads
The image drag and drop works fantastically (see the short demo in the Youtube clip in the summary) and also supports upload to Amazon s3 out of the box.
Pro "Air Mode" lets you create really clean edit areas
Redactor supports a floating edit bar that appears when the user selects the text they want to format. It's really nice if you have trained users and want a cleaner interface. You can also easily modify what icons you want to show. See a demo here.
Con Steep cost
Although it's for unlimited uses, $200 is quite a lot of money.