Redactor (EE 7.3.6) is double-pasting for me in both Safari and Chrome.

A group effort:

• Found that Redactor and Redactor X did not play well with Wygwam fields in the same channel. Pick one or the other for the same channel
• Agreed that the (now) released Redactor X is VERY cool and you should switch fields from old Redactor to Redactor X if possible
• You still shouldn’t mix Wygwam and Redactor X
• Redactor X is easy to work with custom stylesheets. “Moved to 7.4 and were able to replace a set of Wygwam fields that had custom styles defined - which was helpful to resolve some other RTE / Channel Form issues.”