Think of it this way - what you're calling 'styles' are more accurately organizations. To actually know the style a particular teacher is teaching, the organization they belong to isn't the most important thing to know about them.
There are so many different styles within one organization that you should not expect to easily just step from one dojo in an organization into another. Maybe sometimes (e.g. if both teachers came from the same teacher, perhaps, though it's not guaranteed), but sometimes you will not notice that much more or less change by changing organizations vs by changing dojos within an organization.
Luckily, my two main choices in Denmark correspond with my two main choices in Tokyo. The Yoshinkan Dojo in Denmark, has teachers that studied at Yoshinkan Hombu Dojo in Tokyo, likewise the Aikikai Dojo in Denmark has teachers from Aikikai Hombu Dojo in Tokyo.
However, still, people seem to be avoiding the question that I am most interested in, and the question that I have not been able to find anywhere else (hence I'm asking):
Which of the two is the more practical? And what are the real, actual, differences between the two arts? (or possibly others, if you have recommendations).