Compressors are used to compress the sound by a user-set ratio above a certain threshold. You can set the amount of compression as well as the overall gain reduction. Limiters, on the other hand, eliminate all the sound above a particular threshold rather than compressing the sound.
Compressors are well-suited to even out the sound of a certain instrument and are often used on bass guitars, kick drums and snares for a more even sound. Limiters are often used for audio control of the overall mix of a song rather than on individual instruments and can be helpful with other tasks where a compressor is not suitable.
In some cases, a compressor will add a sucking sound when used on an instrument that is simply not desired. You can eliminate this sound by using a limiter in place of a compressor as it will chop off all the sound rather than squash it through compression. The differences between compressors and limiters are slight, but noticeable.