Brittnee's my favourite (by default, but still).
She's the only one who's had the balls to make a 'proper' Big Brother move. None of this walking on eggshells lark, afraid of taking a big player out - she nominated the two people who had been the two previous HoHs and took out the person who was trying to take down her alliance.
She's had solid relationships with Naeha, Johnny, Sarah, Bruno, Bobby and Sindy - i.e. all those who aren't in the Diaper alliance, but she's tried to stay strong with Zach, and despite her and Ashleigh having some sort of dislike towards each other, that seems to have been ironed out, too, and in fact she seems to have a good relationship with Ash now.
Sarah is a massive shield for her, and to be honest, Willow forcing her way into their alliance and taking Britt's spot can only be a good thing for her as more and more houseguests are talking about "Sarah and Willow" now instead of "Sarah and Brittnee".
The only negative to her game, and it's a big one, is that she's not good at comps... but a number of them aren't any good (Willow, Sarah, Ashleigh) so if she can keep her head down whilst some of the stronger guys get evicted, she could really take it up a notch in the final stages and pull through.
I think, overall, she's played the best game out of this lot. They/we all know "pawns go home" and yet she's managed to survive thus far which shows a strong social game. Yes, she might be viewed as weak and that's the 'main' reason she's survived, but you have to have some form of social game play, too. She's also playing with her head, not her emotions, despite what Sarah says. Look at the likes of Bruno and Sarah, they're emotional players. Despite sitting on the block, Brittnee remains cool, calm and collective. Of course she let's out her emotion TO Sarah, she's suppose to be her #1 ally, someone you can trust to let your frustrations out on once in a while.
I don't think she's really put a foot wrong, she made the best move (at the time) when she was HoH, she managed to flip Bobby to vote out Jordan, she's had a good read on the game, and she's played with head.
Pilar, Kevin and Zach have all made pussy moves, whilst Bruno's been blowing up his own game all week and losing his cool because there was a hint of trouble, and look at Sarah during Bruno's HoH, especially compared to Brittnee who had just sent his #1 home. Imagine Sarah being a pawn like Britt? And she's got the nerve to say Britt plays emotionally
I think the only one who rivals Britt's game play is probably Godfrey... but I think he's made some silly mistakes throwing HoH's when he's announced he's after the Diapers.
I'm by no means saying Brittnee's some sort of genius player, but I do think she's the best player of this particular cast (bar Naeha

who just got unlucky with the timing).
When Godfrey/Bobby/Bruno are claiming they can win HoH's but are simply throwing them, then that's not good game play, not when you have FOUR people in an alliance that you know will becoming after you sooner or later.
So, from here on in, I'll be supporting Brittnee, and keeping a close eye on Godfrey... everyone else can leave at any time; they're useless.