Haven't tried it (and that's not based on the fact we already got malloc stuff, PAX, Systrace or Exec Shield floating around nor the fact it's funded by Microsoft and Intel). The title "How to protect buggy programs from security vulnerabilities under Linux and UNIX" is wrong IMHO since it emphasises mitigating symptoms instead of fixing the cause (which it obviously can't ofcourse): instead the *code* should be made safe to use.
And is it really worth using 50-75% more ram usage when runnng Iceweasel/Iceape?
Basically you're asking if it's a good choice to trade off using more RAM for better coverage (less risk)?
If a test of established products vs this one should show they don't provide enough coverage then the answer would be simple. (That is if the Slashdot article didn't mention several people having problems running apps after installing this.) (And next to that RAM is there to be used and the Linux VM knows best how to take care of it.)