the only benefit is that it is better for the environment as our peatlands are getting used up. If you plant doesn't need an acid soil then I reckon that a soil based mix is better eg John Innes 3. Its heavier in the pot so the pot is less likely to blow over, holds water better and lasts longer without souring. take a look at the JI seed and cutting composts too, if not peat free they certainly have less in them than the more modern formulations.
Be careful if you use one of the coir based composts as the smell can be attractive to dogs who eat it with dire results, dogs have been killed by it.