I haven't run witnter tires on the FJ but I do have a set of Blizzak's for the Grand Prix. They are AMAZING!!!! I don't have any other witner tire experience to compare it to but I haven't found any weather they couldn't handle. The Blizzak's get my vote and just to be a "REAL" part of the forum I'll mention these...
Green Diamonds 
I haven't found much about them but they are year round tires and look like they would be pretty good in the winter AND summer. The issue some people might have is that they are retreads. I think that as long as you maintain your tires (air pressure and rotate) retreads should be as good as anything else.
K.... I'm done!
Good luck!!
