Well, I have no doubt Ether will increase in price but take into account the fact Ether supply is unlimited and some huge holders, including Vitalik, hold millions of Ether which can be easily dumped into the market. This is why I am always cautions when speculation on Ether price. I d say $500 is reachable by the end of this year. After that, it all depends on PoS implementation and PoS rewards.