It's hard to say, because there's really not any such effect as a "saturator" in the standard bag of tricks. It's functionally a compressor. Depending on the particular algorithm, a saturator will add harmonics and distortion as it compresses. They've only come along in the past several years as production has continued to move away from analog tape--a saturator is generally a tape-saturation emulator. Their "classic" use in this rather short time period has been on drum tracks, to emulate the sound of tape-saturated drum tracks, where producers overdrive the signal to achieve a particular tone.
Probably the key is discovering what it is about the sound of the saturation plugin that you're attracted to.