[The Artist Formerly Known as Hawk]

It was even better in Dust; You still had the passive xp gain like EVE (1 xp every 3.6 seconds I believe, so basically 1k per hour) but you could also gain xp by playing normally. But only to a limit (I think the daily cap was 24k per day, though it changed a few times over development). After hitting the daily cap you'd get almost nothing, except more isk, which also wasn't nothing (average payouts for missions were around 200-350k per battle, before the costs of your lost suits and weapons (I generally ran with a loadout that cost me around 30k, so I could afford to die maybe half a dozen time in a fight before it started impacting my profit margins)).

This was better in that you actually had to play the game to level up at a decent rate, whilst still being able to leave for months and come back and still make progress in the meantime, but also meant that once you hit your daily cap you felt a lot less incentive to play for the rest of the day sometimes. Also there were real cash money boosters you could buy, both for the active and passive gains (1 xp every 2.4 seconds for passive, or 36k daily cap for active). So an average day playing to your cap limit would net you a nice 48k xp, or you could pay up and double up on boosters and get 74k per day, which if you played every day of the week would certainly add up fast.

Though just like in EVE there was a theoretical limit to how much xp you can effectively bring to a battle; there's only so many shield upgrades, sprint boosts, stamina duration boosts, armor and weapon levels etc, that you can have on a character at once, additional xp then just becomes a matter of versatility in that it allows you to switch loadouts mid battle for an equally upgraded merc, or the ability to call in a decent tank or dropship should you need it. The same applies to EVE and ships, so you can say, go all in on an amazing cargo ship and spent 6 months getting all the relevent upgrades, or spend the same amount of time splashing xp all over the place and get semi decent with a number of different classes. It's pretty good in that someone joining the game years after other players only has to spend a specific amount of time playing before they can effectively match them in a fair fight 1 on 1, with the only advantage the veteran player having more intricate game knowledge and generally more versatility in that they can switch loadouts.