migration assistant or setup assistant? [also connection method]

Aside from remembering to set up an account that does not exist on the new mac is there any real difference between both?

I ask because I want to be able to repartition my drive before migrating things so the fewest possible blocks need to be moved. Then make sure the partition will fit on my SSD.

While I am asking, which is faster, an ethernet connection to my old mac or a connection to my old time machine drive? I assume ethernet because the drive is usb2 and more than likely has been thrashed over the years?

Usually I just manually set up a new mac but wanted to try a normal apple migration this time.

edit: It looks like setup assistant is preferred? Is that still the case? I am concerned about how long it will take, although I am skipping my biggest directory, applications (I want to make sure they all work first and do not need installers).