Oliber, I don't know if I can be of much help.
I completed my MBA at Waseda University and will officially graduate in a few days. Although they are aiming for a world-class MBA, I'm afraid they are not there yet. I've had some good classes and good professors, but many were not so good.
Most (98%) of my classmates were Asian students, and through them I learned that in their country Waseda University is highly considered. Therefore, for them, getting this MBA makes a lot of sense as it will improve greatly their career possibilities when they go back in their country.
I don't know where you are from and what are your future plans, but I doubt a Japanese MBA would be highly regarded in North America or in Europe. The reason I chose this one is because my objective is to work in Japan, and in Japan, the name Waseda is huge.
However, getting a job in Japan after an MBA is much harder that I thought. I've been doing job hunting for a few months already, both Japanese style and Western style, and I realize that traditional Japanese companies don't really know what an MBA is and don't really care about it.
There are two official ways to apply for a job in Japan : apply as a new graduate or apply as mid-career. I quickly understood that if you have work experience and are over 30, you can forget about new graduate offers. Mid-career is tricky as most companies are looking with someone with the exact experience they are requiring - basically you need to have done the job before.
I am over 30, my work experience is all over the place, so you can guess where this is going... really, really difficult.
University professors and recruiters can help, but you need to meet the right people at the right time.
You say you are looking for an executive MBA, so I guess you have relevant experience, and mid-career job hunting could work for you.
Well, I got away from the question... regarding the school, it really depends what your plans are. As someone said before, Hitotsubashi has a good reputation. (although the reputation is not as strong as Waseda - but remember that reputation does not equal quality) A friend of mine just started his MBA in Rikkyo University. I can ask him for some feedback if you'd like.
Anyway, give me more details if you want and I'll try to give you as much information as I can.