https://goo.gl/images/pyJq22 This two artist are doing well in there different genre or style of music. I would not say they are not rising stars, because they've actually brought the African music to a whole new level.
To my own view, in terms of music, I think wizkid is better than davido .considering davido, I can say davido's music is one style of music. Looking at his song 'FIA', the beat is the same with every other songs he has been releasing.
https://goo.gl/images/m5mqta Davido, popular known as 'OBO' (omo baba olowo) meaning the son of a rich man, has captivated the Nigerian Music Industry and he's still doing well but to some extent his music is only one-sided and I can actually predict and tell you that the next davido's new song that will be released would be of the season beat as the previous ones. When it comes out, You'll thank me later.
https://goo.gl/images/LGPKVp 
https://goo.gl/images/g4oN5C Now wizkid. Wizkid Is well known in Africa and international. He's well known for his music and his style of music is mind blowing. Wizkid sings Hip Hop, reggae, e. t. c .
Wizkid is still one of the best and finest musicians in Nigeria and Africa as a whole.
Kudos to both artist, keep the hustle on. Bless up