I like powerbash. I like the way it drops an enemy to one knee for a moment allowing me to get in a free swing on them. I absolutely love it on mages. Running up on a mage and bashing them into submission and then knocking their head off with my mace is one of my favorite pleasures in Skyrim. My warrior really hates mages.
a normal shieldbash gives you the chance to do 2 swordswings till the enemy is ready to attack again
shieldbash - 2 hits - shieldbash - 2 hits
every enemy, no matter who, dies without really touching you. i would even call it "overpowered". it's not of course, since you don't have to play this way.