i think it is really possible that altcoin will overtake btc. btc is first cryptocurrency and thats why it is so popular, but it will change in future, because hype will not longer be.
I already spent almost all my money on buying Eth, but I do not forget about other currencies that may also grow in the future. So buy Eth, but do not forget about the other coins.
Purchasing Eth at a price below 300 USD - an excellent solution. I think in the near future he will fasten the bars at a minimum of 1500 USD. So now I try to keep Eth in my wallet.
Everything is possible, but I suppose that Eth can not hit 220-230 USD, if it reaches this price, we should expect growth after that. That's why right now, you should invest in Eth.
I and some of my friends have been using HitBTC for a long time and do not have any serious difficulties, but we do not have a very large number of assets.