I've actually positioned 10% of my portfolio to USDT. I would have preferred to go USD.
Rationale for my move is that the market is really bearish and may take time to recover - possibly end of Feb - but this may change as well.
Since I also plan to do some ICO's, the USDT is good position to buy eth once it slides further to $950.
With the eth, I plan to participate in ArcBlock ICO