This increase is sustainable.
To a certain extent that might be true, but we can't just assume that the market will continue to go up without experiencing some pull backs. If speculators get the impression that the momentum is slowly fading away, then they won't hesitate to cash out a large portion of their profits, resulting in a correction. Honestly, I don't think we are very far away from reaching that point. I say the top for now will be $1400 to MAX $1450, where after that a correction will happen. I use Bitstamp as reference exchange.
Would it be nice if bitcoin can sustain this price? However, I doubt it will, there will be a few dumps here and there that will pull back the price just a little. Personally, I don't feel comfortable with this price because sooner or later, as you said, people will cash out to make some profit and we can't blame them for that. Its like we are all waiting who will make the first move, then panic selling occurs enough to pull the price down but I'm not expecting to get as low at sub $1000.
