Current direct opponent: Monero
But as you can see in the CoinTelegraph https://cointelegraph.com/news/monero-stratis-continue-to-fight-over-number-10-on-coinmarketcap:
Copyright belongs to CoinTelegraph
...Stratis is "cleaning" the bar with monero. No offense,but once Stratis fully launches Breeze Wallet and Masternodes in about 1 month they should be at least in the TOP 3.
Grab a snack and a beer and watch the show,guys!