To answer your first question... .format just seems more sophisticated in many ways. You can do stuff like re-use arguments, which you can't do with %. An annoying thing about % is also how it can either take a variable or a tuple. You'd think the following would always work:
"hi there %s"% nameyet, if name happens to be (1, 2, 3), it will throw a TypeError. To guarantee that it always prints, you'd need to do
"hi there %s"%(name,)# supply the single argument as a single-item tuplewhich is just ugly. .format doesn't have those issues. Also in the second example you gave, the .format example is much cleaner looking