I joined my local because I liked the women in that group the best. They were the ones that I felt most akin to and comfortable with. I also really, really like the idea of my alum being from the same school as me. We all went to Beloit. We all know the same pains of no dinner on Sunday nights, inside jokes about various aspects of Beloit, etc. I think that being in a local maybe makes you closer to your alum.
Also, being a local, we have more flexibility in which groups and organizations we do philanthropy for. We've held charity events and volunteered for many different local organizations without fear of having to set aside money and time for one larger and/ or nationally known group.
As stated before, most locals tend to have lower fees than nationals. This means I don't have to be more stringent with my budget, but that's not a huge matter in this, as I hear that almost all organizations have ways for those who can not pay higher fees to still become part of the organization (including mine).
As per the hazing issue, if you're founding this chapter and you decide to go local/ regional, then you will have a large say in your ritual and you CAN prevent hazing from being a part of your chapter. I would recommend going to anti-hazing websites to see different definitions of hazing, and if your school has an anti-hazing policy, I would read up on that and see how your school defines it. Then you can make a better decision about what you would like to do for that.
But ultimately, I have to agree with the people who said that it depends on your campus. Here, my sorority is simply the best. That's why I joined it. I didn't know about the whole national versus local thing; I just knew that I was joining a sorority. It just happened to be local, and I love it that way. If going national fits in better with your school, then do it, but right now it sounds like you might want to try the regional thing first. You can establish your group and look at different nationals to decide what is best for your group. No national group is going to say, "Oh, you used to be a local, we don't want you."
But love the locals. If you don't love all of them, just love mine.