Bitcoin + ethereum are the only ones which are worth investing in for the long term. All other altcoins are scams or are not bringing new features to the space and will not succeed based on lack of merit. Remember that Ethereum reacts to the price and news of Bitcoin but it does have some technical differences which make it a worthwhile investment if you prefer to invest in it instead of Bitcoin.
It is that simple and yet people are still always trying to find something wrong with those coins so they avoid investing in them and instead pick a coin outside of the top 200 that according to them it is going to make them a fortune, unfortunately we all know how that ends up right? After a few years bitcoin and ethereum skyrocket again and the coin that was outside the top 200 is now outside the top 1000 and any money invested in it as been lost with no chance of ever recovering it back.