Source: Coin Market Cal
If you are holding NXT, take this great opportunity. You will be getting 1 MTR token per 10 NXT coins. What you need to do is create NXT client and move your NXT tokens to NXT client. Wait for the snapshot to be taken at 1894000. For more info, please refer http://metrodex.org/#airdrop
And yes make sure to sell your MTR tokens as soon as you get it because the price will dump definitely. Also if you are not long term holder of NXT, you should sell NXT right after block 1894000 because price will dump for sure.
P.S. This is my personal opinion and should not be treated as any kind of investment advice. DYOR before any investment.