Safari has been much more stable for me (I get random quits from Firefox - and yes, I've tried deleting prefs and everything to start with a clean install).
I use firefox on my Windows machine and prefer it for one simple reason - SessionSaver and "save all tabs to bookmarks." I do a lot of online research for my teaching and being able to open up a bunch of resources in tabs and then save all those tabs to a bookmarks folder is great. I also love that if I quit the app, it will open back up with all the tabs that I had open at the time. Those two features get a lot of use for me.
Does anyone know if there is an extension for Safari that will do those two things? (1. save all tabs to bookmarks, and 2. save the tabs in the current session on quit, and open those tabs on launch)