I think it has to rise slow and steady for it to be sustainable. Otherwise there will be too many people getting in and out.
There are two types of person in this situation, one that's afraid in volatility of the coin and one that's not. For people that's afraid in bitcoin's volatility they won't stay in this currency and stick into fiat, but for people that like the volatility of the coin they will use it to profit like do a trading.
Well as I can see on what is happening in bitcoin from last month if we are going to base on it. Bitcoin is really rising very fast. It is really too far from its original price for last month which is $400. But now the price is very stable to $670+ and it is really a good effect that bitcoin is continuous rising at all and we must believe it.