Rag mops are very useful because they are more absorbent than other types of mops. They also get into corners and other tight spaces very well. Edge cleaning with a rag mop is often very good.
It can be more difficult to scrub with a rag mop, although strip style mops may have the advantage over strings in the scrubbing category. One of the biggest disadvantages to rag mops is that they are more difficult to maintain. Mop heads must be rinsed thorough and allowed to dry completely to keep odors and germs away. Some mop heads are machine washable, however. String mops can get tangled easily as well.