The Ranger can be described as a souped-up version of the Shock Trooper, with increased range, slightly higher damage, and additional hit points. At rank one, a ranger has 110 and deals 20-24 (3x) damage.
The primary drawback then is their increased cost and difficulty to rank. Due to this, Shock Troopers can level up more easily and will tend to outdamage and outlast a Rank 1 Ranger, and still cost way less to heal. However, at higher ranks, the Ranger will become a formidable unit with decent damage, accuracy and high defense and dodge. The player needs to devote some considerable effort and time to nurture the Ranger's growth.
When they become available at level 20, most players and enemy formations will have armored units, rendering the Ranger ineffective without anti-armor support units.