Using grip and lightning is the most effective way of destroying enemies by throwing the guy and having him explode on impact. I do like using impale, but it's not something I have time to do when I'm grabbing one enemy right after another in a room filled with purge troopers.
I love getting impale and I use it to rack up combos on Felucia against those Felucian warriors amplified by Shamans. You can do it many times against a single enemy without killing it. I also love the ariel assault followed by a Force push. That knocks over any Jedi enemy.