I do think BTC is a runaway train at this point. Due to the nature of the currency I think it can only climb, and it's going to climb fast for a while, and every new entity that jumps into it will just make it more and more legit. I won't say it's crash proof, but I don't think we'll ever see a sub-10k value again. 20% correction only knocks a few 1000 off the price. Something catastrophic would need to occur for it to crash 50%. Hacking, major failure, governments shutting it down somehow...
But because it's global and there are a finite number of coins, it's going to keep going up in the long run. I can see 50-100K next year.
I also don't think we see any major correction while the US economy is booming. BTC could have major growth in the next 5-10 years.
10 years from now 1 BTC could be a $1mill / coin.
It gained 30% since yesterday.
It's up 2100% this year.
It went from $900 to $17k this year.
Even if it does something like 25% for the entire next year, that makes it a $22k coin eoy 2018, and 25% gain is still incredibly great roi.
At this point I see no reason not to invest in it. Going to start making weekly/monthly buys, not going crazy but basically treating it like a 2nd retirement acct.