ETH vs. XMR: Which one is more profitable?

I've been following up on the prices of both ETH and XMR these past few weeks. A few days ago ETH was at around €10 per 1 ether, while 1 XMR was at around €7. However, the difficulty of ETH is much higher than XMR.

Would it not be more profitable to mine XMR under these circumstances? next to the price, what does make a cryptocurrency interesting to mine, or why should one NOT mine a certain cryptocurrency?

Thanks!