Does your audience frequent social media sites? If so, which sites? Is your product something that people will typically buy on impulse, or with a relatively short decision cycle (more usual with lower-cost / B2C products) or is it more of a long-term "considered buy" (common with higher-cost items and B2B products / services)?
Generally speaking, neither one will get you where you want to go all by itself. The best marketing employs a variety of tactics as part of an overall strategy.
It may be that one or the other is better, or it may be that neither one is a good option for you. Without more information on what you're trying to market, your overall strategy, and your other go-to-market tactics, it's impossible to tell.