My first investment in crypto currency was an investment in Bitcoin.
Now I believe that it is much more profitable to invest in promising projects and in altcoins.
That also comes with a lot of risk. I have seen a lot of people losing all their money in alt coins as they completely collapsed. Thus, if you are ready to take higher risks in comparison to bitcoins, then only go for alt coins. I will not recommend them to middle class people with family responsibilities. Such people anyway do not have much money left every month to invest in crypto. They should invest it in safer and reliable option in form of bitcoins. To diversify go with only top 4-5 alt coins and nothing more if you still have some savings left.