Twitch sings is very fun. I'd just like to see better controls for fixing audio sync and testing (there are some but they're not super intuitive). But they keep adding more songs and the chat engagement part is very fun.
I've used this since it was in beta and I recommend it for anyone that enjoys singing or karaoke!
Wide variety of music available (more than you'd think), fantastic Twitch chat integration, very neat duet feature.
Difficult to test audio syncing, not designed to be used with your current OBS/SLOBS setup.