I have spent all of $9.99 in a full 7 months of playing this finely crafted game.
And I pretty much bought a special offer I could not resist. I MOSTLY justified the purchase as a fair payment to the developers for playing the game as much as I do
As far as Pay to Play whiners... I find the progress with which my unit levels have grown has matched my skill progress quite closely.
It's hard to believe that those who complain about about spamming or those who pay to level up can actually compete in leagues that are out of their real skill level.
As some replies have noted... You need TO LEARN how to stop the player who's strategy is get out one or two disrupters. You may also be easily beat by 5 bike squads and a laser troop.?
I have learned those lessons by playing. And the $10 I spent was not in ANY way part of those lessons.
If one had all level 13 units...
Without true mastery of the gameplay
The Tiberium League is an impossible accomplishment.