XRP (Ripple) : I feel it is a long term bet since it has the support of banks like Standard Chartered and Merril Lynch.

SIA (siacoin) : After looking at their website I feel that they have made one of the best uses of the technology. Most other coins only market themselves as currency/safe storage/ easier transfers , wheras siacoin is marketed
for anonymous data storage. Siacoin has lesser competition in that use of cryptocurrencies. Since the value of the crytocurrency lies in the underlying technology, I believe its a good bet.

And of course, STEEM, which also has less competition in this sphere as of now.