my only issue with Firefox on Mac is that streaming video from twitch will just randomly stall but this did not occur with Safari. The oddest part is that is stalls randomly when clicking back to the tab with the stream. Even with multiple streams its wholly random if one will stall the video portion or not; the audio continues and chat bar works too.

memory wise it will consume quite a bit when managing streaming content and even leave the code in memory when all related tabs are gone; I assume this happens because of the dearth of video content on many web pages