In my opinion, the best place to get Ninjitsu training is in Japan with Master Sokee Masaaki Hatsumi and his top Shihan teachers, because that's where I went.
Their knowledge and skill level is second to none. So I would say that you're teacher is your number one goal in finding the best Ninjitsu training and the best teacher out there is really Sokee Masaaki Hatsumi.
He is the best place to learn about Ninjitsu because he has the knowledge and experience and skill level and talent to demonstrate it. Because it's not an intellectual process, it's something that has to be experienced and you have to breathe it. And it's like playing an instrument, you have to be able to see a great artist. And experience their art in order to really absorb something from them. And that's the process that we're talking about.
It's not a technical, purely technical process. You have to go and really experience it from a true artist which Hatsumi sensei is.