

The most comparable would be Enclave-Brotherhood and Ranger-Centurion, with the former of both probably coming out on top in general, however it would depend highly on the situation. Plus, to be a Centurion you must be a veteran, meaning that they have more experience than your general soldier. From their depiction in the game, it does look like they are about on par, with exceptionally good long range weapons (like the Rangers) and have exceptionally good short-range weapons as well. Legion Centurion: It's said by some members of the NCR that they're about on par with their Rangers and are extremely well trained in skirmishing tactics.

The equipment and training are basically equal as far as I know. There's also the Veteran Rangers, but as far as I know they are basically just Rangers who have been Rangers for 20 years. The Brotherhood has to rely on scavenging and trading to get its materials (at least on the west coast), but the Rangers have factories and taxes. Also, they have the backing of an entire civilised nation.

They would be the type of people that would be sent to fix any military situation that others can't. As a comparison to IRL armies, they're basically a desert version of the SAS. They would be much more sneaky and probably are able to go radio dark for weeks, if not months. They would usually not engage in normal combat, more likely they would be sent to command a base to raise morale and standards or would engage at long distance. NCR Ranger: Extremely well trained in their environment (desert) and exceptionally good trackers. Their Paladins would probably have better equipment, but still similar training. However, the West Coast is a different environment. In DC in 2277, they couldn't win without Liberty Prime against a force of Enclave probably half their size.

They develop some tech, but nowhere near as much as the Enclave. The Brotherhood: Likely similar training to the Enclave, but more adapted to the wasteland and less resources. However, they are troops and would not fare as well as the others by themselves, as they probably aren't good scavengers. Their troops are probably on par with the US Marines or even the UK SAS. Enclave: Proper military training and the backing of an extremely advanced manufacturing base. They're all very different in terms of training and fighting style.
