Well, after a long grind, I can honestly say I feel relatively accomplished for getting all of the Master titles associated with each style. Perception of diffoculty may vary by your skill level with and ability to adapt to each style should you do the quest. I will say some are definitely very lenient compared to others.
There's also a title called Transcendent Blademaster from a... Well, I can't say any other fight the singleplayer offers is as stressful. I definitely learned quite a bit due to that fight and broke some bad/old habits. Also progress dealing with my weaknesses. That said, now I cam finally focus on actual training, and learning more advanced combos and such.
I can't say I had anything against any character before, and this solidified that. Nothing any player can do to me without magically modfing/hacking the game on console could ever match the level of bullshit that last fight is capable of. It was fun though. Now to enjoy other modes until 2B drops and I inevitably go for her Master and 'Soul of' titles as I'm sure there will be.