I think that now would be a safe time to purchase ETH for fiat considering how low the current price is. On the other side of the issue, however is the fact that it may be a better strategy to wait for a clear sign of a bull run and to buy in when that starts to occur. If you think that the ETH platform/project is going in the right direction then I don't see any reason not to take some stake now. If you are extremely vigilant though waiting out the conclusion of the dip may be a better idea. All depends on how you view yourself as a trader and on the entirety of the market and ETH platform.