I didn't say "difficult", it's tank-yness and quick speed allow you to deal with most opponents and leave with barely a scratch. But I find the perk not that pleasing to play as... Unless you use the pulverizer or eviscerator. I know that not every perk is good against everything, but I also struggle to bring down tougher opponents for some reason. Even with a high-level skill tree and the ability to parry.
I won't lie, I believe it's just me rather than the perk itself. But it makes for a frustrating experience, and I have no real arguments as to why.