Looking up the description for the Unsullied, they wore quilted armor, shields, spears, short sword and fought in a phalanx. A shield is one of the biggest deal breakers in warfare..it cancels out a good many things. Especially with a long spear and a tight formation, making it almost invulnerable to frontal attack which is what the Dothraki did at Qohor because according to the source material, they made no effort to outflank the Unsullied out of sheer contempt for the infantry. (shades of Agincourt !) The fact that only 600 Unsullied survived out of 3000 at Qohor says something about their morale, not to mention the Dothraki who lost almost all of their horsemen. So..you could say Daernys has two of the most fanatical groups of troops in all of Westeros and Essos.
In historical terms, the Unsullied come closest to Alexander's sarissa armed phalanx except that the Unsullied had shields and shorter spears. Unlike their successors, the Alexandrian sarissa armed phalanxes were remarkably flexible and mobile - the Successors armed them more heavily and with less mobility.
The Unsullied quilted armor also comes close to being similar to the linothorax armor worn by most of Alexander's troops. They were the ancient version of kevlar armor. Tests have shown that 16 to 24 layer linen armor glued together with animal glue was VERY effective in stopping ancient missile weapons and up to a point, even spears. In fact, Greek Age arrow fire couldn't even penetrate 20 and 25 layer linothorax armor.