Combat arms is made up of the best bits of all the best shooters.
The game maybe superb but there are a lot of flaws within it. One of these major flaws is the ability to easily hack. In certain maps you will see people flying all over the screen shooting you no matter where you are. Another flaw is the price of the of the guns, clothes and perks. There are a few free stuff but you can only keep them for a little time. The stuff that costs money normally is around $10au for 1 month of a gun. Which to me is a lot of money.
As a free first person shooter with little flaws, Combat Arms is worth free, easy the download.