I have an 05 LLY...knock on wood, no known problems.  I change the fuel filter with a Racor filter every 10k miles and run Stanadyne every tank....plus only fill at high volume stations.  Is it expensive to replace the injectors?  Yes, especially if you want to get some good remaned ones.  Is it worth dumping a whole truck that is capable for a potential $700-$1000 payment for a new truck?  Nope.  
I also keep money in the bank for the head gasket job, if and whenever that may occur.  This is a great truck, and it doesn't cost me new.
Cale