DO NOT BUY THE LINE 6 CONSTRICTOR!!!! It is by far the worst compressor pedal out there. Compressors are indeed hard to use, I can never seem to find just that right setting on mine, volume wise. Sound wise I get the nice percussive clicky sound on leads. You hear compressors alot in country music.

The Ibanez Tubescreamer, depending on which model, is definetly more of a add-on to a nice tube amp. I would never use the tubescreamer alone ( I have one ). I always use it to boost up my overdriven tube amp and the results are great. Others you may want to look into are the BOSS Blues Driver and Super Overdrive.