another question, what are the basic differences between aikido and ju jitsu? does one art concentrate on one technique more or something else?
The difference between aikido and the jujitsu style that influenced it most (daito ryu) is that aikido focuses on learning principles. O Sensei took a large syllabus of techniques and condensed and modified their usage and teaching into a comparitively small number of principles. (He explained this in "Budo")
For instance, the principle of Ikkyo replaced, I believe, 30 simular techniques which had to be mastered in the Daito-Ryu. And so forth.(I source this from an interview with daito ryu sensei Katsuyuki Kondo on the aikidofaq. random quote "Ikkajo consists of thirty techniques, but only the ippondori technique became ikkyo in aikido.")
What use this has to your deciding which to choose I don't know. Try both and see which you're interested in sticking with. You might find you're not interested in either after a month.