[Eden Eternal] Closed Beta Finale Party! (screenshots inside)

True that Reg and Class skills can be upgraded as much as you want, but the main problem is that the cost rises exponentially. In the case of the former, it doesn't just burn a hole in your wallet; it burns your entire wallet to ashes.

That's manageable though, the fact that it's infinite means you have plenty of time to save up to upgrade at least.