The bull ride will continue as long as there is a negative news in the market and it is hard to know that until and unless you see that in the market.Lets see whether the coin could break $1700 and then we can talk about the rest of the valuation .One thing is that 2017 is the best time for crypto currency because each and every coin had a very good rally.
That is a bit disturbing, we have never before experienced situation where 99% of altcoins and bitcoin was pumped before.
Crazy rise like this is happening for the first time. It is hard to tell how much altcoins really grew and how much of it is irrational speculation.
Here is a good article about the situation on Coindesk:
http://www.coindesk.com/25-billion-30-days-cryptocurrencies-bubble/This may indicate that some whales have joined forces to try to inflate the price and get more earnings than before, it could also be a concerted effort by the governments or bank to try to break bitcoin by making it even more unstable and to destroy the confidence of investors.