You have no better time than now to buy this game. For the price of the Apex expansion alone, you can get Arma 3, Apex expansion, and the DLC bundle. $70 worth of content for $35. From the 3 hours I have played, it is worth it.
If you're considering Arma 3, definitely consider it NOW during the sale.
I'll write a proper review of this game once I put in a few more hours. I've only experienced single player so far.