dstiles - 7:10 pm on Aug 6, 2013 (gmt 0)
The mixed-content blocking by default is good. I've had it set to block for years and build websites accordingly.
I think FF needs to be improved a LOT more, including full provision for the latest TLS protocol - TLS/1 is another exploitable protocol.
Firefox is still, in my opinion as a daily and frequent user, one of the best and safest of browsers but it could be a lot safer, within the context of a badly broken internet.
Lots of info about all of this on threatpost[dot]com.