Nihilist:
Actually, I disagree with Sacred Band being second best to Spartans.
I've done some extensive testing on spartans versus Sacred band and Sacred band win out at equal cost.
Obviously, at basic cost for each, spartans win out due to their hitpoint advantage, but if you upgrade the sacred band with 2 chevrons and 1 weapon upgrade (its something like 60 denarii difference - sacred being cheaper) then the sacred will beat the spartans in a standard phalanx battle hands down.