My best coin so far has been Ethereum, although I like bitcoin but Ethereum still remain my best for now, because it is easy for me to exchange it into my local currency.
Yes, I believe ETH will still be the best altcoin in the next few years. There are some other altcoins that have great potential to surpass ETH in the future, such as EOS, NEO. However, ETH is too popular now. So I don't think any altcoin can surpass it at least in the next few years.
It's more popular because XRP has surpass it's standing, lol.
But, I don't really think it's a big deal because this things that are happening now are just temporary, in fact I am betting on ETH for short term
and with the current price, I believe it will rise again and will definitely bring great return to those who invested now.