What do you want out of your martial arts experience? Not what do you think you
should want, but what are you looking for. That's what's important. The answer may change. For the moment keeping the question in mind is the key to making good choices.
There is a number of reasons people do martial arts - the joy of competition, socializing, physical fitness, connection with a culture or historical period, self defense, more subtle personal development, an outlet and many others. No one school or method can excell at all of them.
It is more important to find a school which is compatible with these goals and a teacher with whom you will be able to spend the time and energy than to find a particular style or tradition.
That said, there are some systems which are better at some things and for specific people.
If you like to wrestle you will be disappointed with fencing. If you want to learn ancient weapons Krav Maga is not for you. If you have short legs and little natural flexibility you are runing into your weaknesses if you do Tae Kwon Do. On the other hand, if you enjoy precision, control and the sword fencing is perfect. Krav Maga is a great choice if your primary goal is practical self defense in a short time. And Tae Kwon Do has become a very popular international sport.
Go to a couple classes at each school. If they won't let you watch or try to get you to sign up right away, especially for something like "free course of five private lessons" turn around and walk away without saying a word.
Look at how the class goes. Watch how the students interact, their level of energy and interest.
Look at the space. Does someone care about it enough to keep it clean, safe and in good order? Are there lots of trophies? That would indicate a school that is geared towards competition. Are there uniforms?
What sort of skill do you see in the senior students? Skill in the instructor is important, but you're interested in learning. Can he transmit it? Does anyone stick around long enough to develop to a reasonably high level? How much does the senior instructor actually teach as opposed to standing back and watching while his senior students do the teaching?
How hard is the sell? If the teacher promises to give you the Mystic Wisdom of the Exotic Orient or the Exotic Wisdom of the Mystic Orient you're probably being scammed. Anything that you really put your heart into can be a vehicle for personal growth. And most martial artists are no more functional as awake, aware, spiritually mature human beings than anyone else. Often quite the opposite
How much emphasis is their on heirarchy, status, ranks and titles? How much of it do you want? How much are you comfortable with?
A school whether it's a huge establishment with dozens of teachers and a kids' after school program or half a dozen folks who get together in someone's backyard has its own life as an organization. What the school as an entity does for (and to) its members may not be what you are looking for, but it may well be close enough that the ride is worth the fare.