If I am going to pursue "becoming like God", I want it to mean something vital and empowering.
I want to believe it is a "real" goal, not just a platitude. I'm not 100% certain of much when it comes to the afterlife, but I at least want to believe I really am an actual child capable of becoming like my actual father.
I don't like the warped perfectionism I see in many people (including too many LDS members), but I will take it as the flip side of the wonderful emphasis on godliness that is embedded so openly in Mormon theology. I want to be striving for exaltation, not be complacent in salvation. I know that seems to be an over-simplification, but I think it's a pretty fair summary of the difference between the actual theologies of Mormonism and other Christian sects.