It's hard to say exactly what the future of cryptocurrency will be, but masternodes definitely have a lot of advantages.  You mentioned the fact that they are much more energy efficient than typical mining, but they also help with transaction privacy and instant send.  One key barrier to entry in the masternode sphere has been the relatively large stake required to launch a masternode, but some hosting sites are beginning to offer shared masternodes, in which several investors can pool their coins in order to launch a masternode.

It depends on exactly what you are currently holding, what your investment strategy is, and how risk averse you are.  If your plan is to sell now, only to buy again as the price goes back up, I would recommend holding your current coins because selling now and buying in again at a higher price will only cost you more money in the long run.