Has any one used Quaker State Concertrated Fuel Injection Cleaner before?
I got is as a free sample when I bought some quick detailer at a car show.
Is it any good or should I just get rid of it?

They are all pretty much the same regardless of brand, just concentrated detergents. If you use a good quality fuel (not talking about octane) it should have enough detergents in it so you shouldnt have to add more.