There will always be better alternatives, but Steemit is the first to market (as far as I'm aware) with the blockchain-social media concept. So while competitors will try to steal the thunder away, Steemit would have already gained tremendous traction.
The caveat here is that Steemit needs to resolve certain vulnerabilities, such as the downvoting system or the problematic de-facto censorship. But overall, I'm bullish.