the only safe investment among cryptocurrencies, specially when you are thinking long term is bitcoin and nothing else.
other altcoins can be good too such as litecoin and monero and even ethereum but it is best if you treat them in short term not long. meaning buy in a dip and sell when they rise to add to your bitcoin holding.

ethereum can be profitable but it is full of problems and has some bugs too. there are some good news on the way and it may be pumped again, but i am waiting for a good opportunity to get in and seek profit. for now bitcoin price is rising up again and in case it rises suddenly and big, ethereum price may drop.