You get xp & c-bills, just at a lesser rate than someone who pays for Premium.
So if you are really into it, there is a bonus - but like any game where you have to grind a little - you could be playing a lot and not need Premium vs someone who plays a bit less but uses Premium to counter it.
That said as long as the matching system is decent, and not anything like the abortions that Blizzard have used for years, then it should be great