FrogReaver
The most respectful and polite poster ever
Interesting debate! Now I am considering dipping into Battlemaster Fighter for 3 levels (I'm already level 11 so I feel like I have enough ki... I'll be sad to miss out on proficiency in every single saving throw at level 14, though).
Re: Stunning Strike vs. superiority die: Remember that Stunning Strike allows a Constitution saving throw; some of the guys you'd really like to stun have very high Con. A superiority die is just straight up +1d8! That's pretty tempting.
more ki for more stuns and flurry of blows + those other abilities is better than superiority dice.
It's not like superiority dice is a bad option though.