We prefer Waves platform because it has the WavesDex official from the Waves Platform. It just shown that among other emerging smart contract platform they have more concern on how their developer's token could be listed in the exchange. Ethereum may have many decentralize exchange too but it is not official. In term of Gas (transaction fee) waves platform is way more efficient than Ethereum, and their scalability is not significantly different. Waves still guarantee fast and stable transaction but has less fee.