Whether you mine the coins or you buy them now, according to you which of the Alt coins is worth holding and sell them after a minimum of 2 months?
the best coin to hold is bitcoin and you should hodl it for a much longer time than just 2 months.
but as for altcoins the promissing altcoins to hold for long time are LTC, LSK and two more that i will not name now becasue i am still investigating.
and if you want to trade for short term buy and sell 2-3 days then both etherum coins are good.