Well if you check coinmarketcap for steem
https://imgur.com/a/zdahA
you can see that it's currently at an ATH (all time high), so I would not advise to buy it now.
A good entry point would be around 3.5$ USD. But since steem has a legitimate product behind it (steemit.com), I say it has room to grow.
Converting/comparing the price of STEEM to BTC, which is the price of STEEM 6$ USD x (STEEM calculating supply 246,246,336 / BTC calculating supply 16,789,325) which brings us to the price of 88$ usd compared to 15549$ USD that bitcoin is currently trading.
We can see that STEEM has the potential to go big in 2018.