I couldn't figure out how to delete my previous review, so I'm leaving another one. I previously thought that Tabliss was causing Firefox to lose its startup preferences, but after lots of testing - it's NOT Tabliss. It's a weird FF issue. Tabliss is awesome! So, I'm definitely sticking with it!
Also, a side note, Joel at Tabliss was super fast to try and help me trouble shoot, even after we figured out that it's not the add-on that's causing the issue. So, kudos for awesome support and responsiveness.
You guys are awesome!