World of tanks: Researching certain technologies before being able to advance to another vehicle. Paying to obtain a vehicle with some vehicles only available for real world money. Repair and resupply costs for your vehicles after damage or using ammo.
League of legends: Buying mechs for either in-game currency or real world money. Some visual enhancements/changes only obtainable with real world money. No need to unlock certain technologies before being able to buy a certain mech. No repair or resupply costs.
World of tanks without repair/resupply costs: Same as WoT, but without repair/resupply costs after combat.
League of legends with repair/resupply costs: Same as LoL, but with repair/resupply costs.
Obviously there are other differences as well, but to me these were the most important/obvious ones

I'm curious what you guys prefer

