Meh, the piano chords at the beginning are very nice but any spoken word over it just ruins it and just isn't needed. I think it ruined an otherwise nice intro. Rap isn't something that I like. But I think you've done a really good job on this overall. It's not as copy-pasted as some other rap stuff I've heard. The chords are nice, the lead synths repetitive melody is also cool and the rhythm of the rapping seems to be punctuated pretty well. Although it sounds a bit distorted. I have trouble following lyrics of normal songs, so I had little chance following this. I thought the structure was fine too.
Mixwise, not really sure on specifics but the vocal track needs to have considerably more clarity, especially so given the words are faster than a regular song. I'm not familiar with the professional rap songs so I can't really compare, but nothing stands out as sounding that out of place, aside from the intro and outro's spoken word parts. Well done overall.
By Cubase Mediabay you mean you used a pre-recorded/programmed loop?