I couldnt tell from the videos I watched, are you able to use your opponents vehicles and what not in Arma?
Yes. Whether it's enemy players or enemy AI, bodies are full loot, unless otherwise dictated by the mission you're playing. Unless a vehicle is locked by the mission designer you can get in and use any vehicle, friendly or otherwise.
It's a military sandbox like no other game on the market. No XP, no levels, no run & gun FPS 'no scope' leetness. No subscription, no premium packages. Do it for the fun and the 'remember that time...?" moments.
Different game modes like CTF, DM, King of the Hill, various co-op vs AI missions (my favorite), singleplayer missions, official campaign, etc. Lots of content and mods created by the community.
It's more realistic, without being a simulator. It's a bit more slow paced compared maze shooters like BF and CoD.
edit: The exception for getting into vehicles applies to DLC vehicles and the upcoming DLC weapons. You can still play in missions with DLC owners without buying the DLC yourself. You just don't be allowed to pilot DLC helicopters or pick up DLC weapons.
