It depends on what you want to do. Long term investment or day trading .In my opinion you can invest in both bitcoin and alts but be aware about the basic principle 1) when bitcoin goes up altcoins goes down 2) when bitcoin goes down altcoin goes up 3) when bitcoin is steady altcoins goes up. Volatility is also a factor but with high volatility if you know basic chart reading there is a possibility of high profit but high risk also. Overall since bitcoin has already establish itself it's the safest and you know that it's have more room to grow.