Difference between College and standard editions of speed building?

I am looking to buy either "Gregg speed building for colleges: Simplified ed" or "Gregg speed building simplified" and I'm wondering which would be best. My Simplified is getting halfway decent, although I could definitely use more practice in order to get down all of the abbreviating principles. Up to now I have focused far more on accuracy than speed. Any recommendations? What's the functional difference between the editions? Does it make sense to get both? (and, if so, which is best to start with?)