Bitcoin (rated C+) gets excellent scores for security and widespread adoption. But it is encountering major network bottlenecks, causing delays and high transactions costs. Despite intense ongoing efforts that are achieving some initial success, Bitcoin has no immediate mechanism for promptly upgrading its software code.
Ethereum (B), the second most widely adopted cryptocurrency, benefits from more readily upgradable technology and better speed, despite some bottlenecks.
Novacoin (D) and SaluS (D) are weak in terms of both technological innovation and adoption.
Steem (B-) enjoys a relatively good balance of moderate strength in nearly all the key factors considered along with a social network feature.
Cheers Steemians! :)