At this time bitcoin the only coin or the best currency and deserve to be ranked No. 1 and it has been proven concretely. In addition to being the best currency Bitcoin has other excellent features such as:
1. Can be used as a tool that can be traded similar to gold.
2. Its prices are unstable or often experience a drastic change in value (Volatile).
3. Bitcoin prices are never unbeatable by currency or any coins including altcoin.
4. In any situation the decline / increase of bitcoin is very interesting to note especially for investors and traders.
I think until now there is no currency that can beat the popularity of bitcoin.