Hi Thank you for your question. I think there are two ways to answer this. Firefox Developer Edition is a pre-Release version of Firefox. It may come with one or two bugs that are being worked on before it moves to Firefox Beta and then the main version of Firefox. I use Firefox Developer Edition myself as my main browser, there is nothing wrong with doing that, but please appreciate that is the not quite finished yet (this is why there is no Release versions of 64 bit Firefox...yet). Subject to any connection issues, the only other thing that you may want to look at is the Flash plugin that you have. If you are viewing videos on Facebook (and YouTube) you do not need the Flash plugin. If you [https://support.mozilla.org/en-US/kb/disable-or-remove-add-ons disable or remove] it, you should be able to view the video natively in Firefox. (I have just noticed that your version of Flash is out of date. This [https://support.mozilla.org/en-US/kb/keep-flash-up-to-date-and-troubleshoot-problems article] will walk you through updating it.) I hope this helps, but if not please come back here and we can look into a different solution for you.