Regarding Horsemen or Swordsmen, the Horsemen have the additional advantage that because of their speed they can attack more enemy units in open terrain. So, on average, they are facing a weaker opposition.
It is also easier to make a co-ordinated attack on one city and take it before the enemy can move in and/or rush-build additional units. As a consequence, Horsemen will also face less opposing units.
Swordsmen, on the other hand, have a better chance to get as well as survive a counter-attack and thereby receive an automatic promotion.
It is also easier to make a co-ordinated attack on one city and take it before the enemy can move in and/or rush-build additional units. As a consequence, Horsemen will also face less opposing units.
Swordsmen, on the other hand, have a better chance to get as well as survive a counter-attack and thereby receive an automatic promotion.