There will be differences in financial packages, the quality of the programs and geographical locations. Your top choice might offer you admission but not financial aid. Your bottom choice might offer you an attractive financial package, but you may have doubts about the educational opportunities there. Your own undergraduate institution might seem like a safe haven, but many would advise you to broaden your horizons and go somewhere else. Some programs require a thesis for the master's degree, others don't.
Some programs take twice as long to finish as others.
Some places offer financial aid for the first year while others offer financial aid for the duration of your studies. The variations are endless. I could not have gone to graduate school without financial aid, and it is an incredibly important part of the process. But, comparing financial packages can be tricky. For example, differences in cost of living often exceed the apparent differences in financial offers.