Thank you! I agree, bitcoin is the strongest and hopefully it will be improved soon with segwit and 2MB blocks to enable it to scale further. At the same time, even given it's network effect and head start, it's not completely out of the real of possibility that some altcoin will get just the right backers and marketing spin to become a real threat to it.
So far, I'm holding. I can imagine buying back in later at higher prices and that gives me pause.