Grit has a much smoother transition than Oaths. Anybody saying otherwise is delusional.

You basically do the exact same thing DRKs do except you need to blow a GCD to swap to Sword Oath. You are dropping Shield Oath through buff cancelling as not to break your combos but still cancel the damage penalty, and at a time where it's more convenient, you activate Sword Oath. It's a DPS loss to wait through RB + GB or SB + RA/RH in Shield Oath rather than drop Shield Oath through buff cancelling after a FB and then activate Sword Oath after the GB or RA/RH.

So, in the end, how you transition from Shield to Sword is constantly changing. You can either straight swap if things work out with your GCDs and combos or you have to drop and swap if they don't. In the end, you have an incredibly clunky stance dancing situation.