The metro (subway) is the fastest way to move around the city, but the buses, both in the capital and the other big towns, are best for taking in the sights.
The metro and bus each has its own merits. 
mnli hypothesis: The metro and bus each has its own merits.  premise: The metro (subway) is the fastest way to move around the city, but the buses, both in the capital and the other big towns, are best for taking in the sights.