It'a all about the basic techniques.
I've trained for 11 years and because of my father's job i have been able to do Seidokan, Iwama, Aikikai (in mexico) and Bu Iku Kai. I actually teach Bu Iku Kai because is the Aikido that fits best to me.
I had the opportunity to train with very good teachers (even if they did a differnt style) and i have come to the conclusion that if you learn the basics of any style you'll be ok, your technique will work.
Of course if your teacher is a charlatan (i hope that's the correct word in english) you can do any style and your technique will never ever work, it really depends on the teacher not on the style..... i think