TGP & Free Sites aren't exactly the same category - remember:
TGP is to Link List as Galleries are to Free Sites
Of course, with every free site you build, you're probably building 2 galleries as well, so save copies of those & submit them to TGP's - it's like killing 2 nirds with one stone
As far as what converts better, I think it's party due to what you like & thus are able to honestly market to the surfers.