I love the concept of #5. Thanks intrepidguppy!
I'm not crazy about the actual look of the S/brain graphic, but I love the idea. I've been trying to figure out why I don't love the look and I'm a little stuck. I think it's partly the shape -- I have a hard time seeing it as a brain or an S. Is there a way to play with the shape (without being too literal) so that the concept is more clear? Do you think a little dimension (feeling of 3d) would help?
Also, the colors are bothering me. Which is funny since I really do like grey and blue ... but as I see it in the designs it feels stodgy to me. I'm not going to make color suggestions since I did that in my brief and just overruled myself. I wonder if you have suggestions that would feel less stodgy.
Also, I don't want to use the line "things make sense when you know the truth" in the logo ... it's a good strategic line but not good copy.