Re: Tenshin Aikido
Yes, there can be a wide variaty of techniques between dojo, especially dojo with different affiliations. I would personally enjoy training with either the Doshinokai dojo (I have met and trained a very little bit with Matsuoka Sensei), or with Obata Sensei's group (I am affiliated with the Yoshinkan, where Obata Sensei spent quite a bit of time). Yet the waza that the two schools train is probably quite different...and I would expect that Matsuoka Sensei's school at least is different again from the Tenshin schools that maintain a link with Seagal Sensei. This is because Matsuoka Sensei is now studying under Abe Sensei (I believe), and the focus would be quite different from what he did with Seagal Sensei.
These differences are really something that should be felt for oneself...it is not something always easy to describe in a web posting. You should go to each of the local dojo, and make a determination for yourself based on how the instructors and seniors perform, how they relate to the students, and how you react to the teaching methodology (which often is what varies the most between dojo...sometimes even in the same association).