Both coins are better to invest but it depends on what type  of investment you want to do. Bitcoin is the best to invest if you want long term investment. It also give you a huge profit. Buy bitcoin now since price is still dump and low. Hold it for a long time until price will rise to the moon, then sell it. While, if you want a short and fast income go for altcoins. Their are ICO projects that has a promising platforms and you can get not so high profit but monthly.