Entry #4 is pretty interesting. It hints at a smiling face which is pretty neat. Is there a way it could possibly incorporate two f's within the box - to symbolise the fact that fundsforum is about communicating with others (the experts in particular). Might get a bit crowded perhaps. I guess the two f's wouldn't have to be the same size - or could be in different colours. Anyway, just a thought...
On reflection, I reckon entry #4 outshines entry #6 except perhaps for the business name. I like the idea that the two words are in different colours.\
I'm liking the face. I like the eyes being slightly off-centre per entry 49. Perhaps this is the way to go - to add more depth or perspective to the character.
The grey background works better cause you can see both f's clearly. Which suggests a potential problem - that the design can't be seen in silhouette (or not with the background anyway).
I prefer the two-colour name as well (per entry 57)