I don’t think NWM has true own occupation.
I have Principal and havent had any issues with insurance (retirement accounts, on the other hand....)
I assume NWM is Northwestern Mutual, in which case they do offer true own occupation. If I'm not mistaken, it may offer better protection for surgeons and other procedural-based specialties. Often if you're a surgeon and are unable to operate but can still run a surgery clinic, disability insurance wouldn't cover you. Northwestern has (or at least had, when I applied for coverage) a medical own occupation rider that would cover you if you can't perform some of your listed job duties.
With that said, I don't do procedures. I went with Northwestern because other policies turned me down or had ridiculous write offs. Berkshire said because I sprained my hand early in training (with no residual deficits, only one XR and Dr appt needed, got NSAIDs for 2 weeks), that anything that happened to my RUE would not be covered. So if I became disabled due to carpal tunnel syndrome, an amputation, etc., I wouldn't qualify.
That is why it is important to apply for disability insurance early-when you're young and healthy (ie, intern year). It is ridiculous how many things they will carve out, and how easy they will deny you for the smallest of things.
Northwestern isn't considered as big as Principal, Mass Mutual, or Berkshire (I think they changed names). Only NML salesman can sell NML policies, whereas insurance agents can offer you policies from all the other big companies. And Northwestern is a little more aggressive than I'd like on marketing (I had to ask my agent to stop asking me if I could introduce him to co-residents, etc.). But at the end of they day, they approved me when a few others didn't, and their policy didn't have the limitations that others had.
I recommend applying for insurance with multiple companies, and seeing what you get.