Problem with the heel hooks is that they are hardly ever useable in tournaments over here. A blue belt (not for long) from my gym, Will Gould, wrecks house with them, and has shown me a few nice tips.
I really like leg locks, but according to the IBJJF rules, they aren't acceptable at blue belt at all, only the straight ankle lock is allowed at purple belt, and then everything at brown except for heel hooks. Problem is, a lot of comps here use those rules.