One of the best game ever and core engine for VBS - Military simulator, used by many military universities and academies like (US - West Point, USNA, CZECH - University of Defense, New Zealand Defence Force, Australian Defence Force, Canadian Armed Forces, Royal Netherlands Army, UK Ministry of Defence, etc...)
It was shipped without any game-breaking bugs, and it became an international success, selling more than 500,000 copies in its first three months of release

pros:
cheap
low requrements
basic simulator
lots of mods, models and texture packs (not only workshop)
mission editor for SP & MP

cons:
AI waypoint bugs

neutrals:
difficulty - hard for beginners, normal for advanced and pros