I think stellar is one of the best altcoins to buy in 2018. Stellar has additional room to run. Unlike the scalability-challenged bitcoin, the stellar blockchain closes transactions within seconds, not hours or days. As the blockchain concept becomes an everyday reality, transaction speed will be critical. Furthermore, stellar extends the lightning-quick transactions to fiat currencies. For example, users can swiftly convert dollars to euros, rather than relying on cumbersome and expensive banking institutions. Recognizing the potential, International Business Machines Corp. (NYSE:IBM) uses the stellar blockchain to develop a payments system with large banks.