I'd rather be in Dog Fight than in Half Guard flat on my back (or whipped up on my side). As I'm trying for Half Guard Sweeps, I'm always looking to come up on to my knees and do battle from there. It's like an improvement on position (since your up on your knees rather than being on your back/side) and makes certain sweeps easier. For instance, it's easier to Half and Half some one than Old School, and Plan B & Twist Backs are easier since you can build more momentum (dropping into it). I also like the fact that you have way more chance of taking the back with a limp arm, Mookie or throwing in the back hook, then you do just whipping up and hoping the guy forgets to put the whizzer in.
Also, if you have a good whip, you can whip straight to Dogfight every time, getting you up off your back/side. Just watch out for the 100%. If so, use the Boa to get there (safest method) or the Dip Set.
Don't forget to put the Twist Back hook in. It dramatically increases your control and stops the opponent from hipping in and limp legging out.