Currently I haven't bought any single altcoin yet because I do not have the fund and capacity to do it right now so I am collecting funds first by joining promotional campaign in ICOs. Once I have enough fund then I will do trading and I will buy altcoins as investments. Bitcoin is the primary cryptocurrency now but I personally believe that altcoin is a good investment. There are may good altcoins listed in exchanges with good performances in the blockchain and are worth investing. Etherium coins I believe are good crypto and are mostlt bought if I am not mistaken.