Skillwise...
Mega is a great writer, he has a shaky flow, and he stays always sticks in this lane delivery and flow wise. Conceptually he is tight but he sticks to a tried and true straightforward approach.
Saigon is a good writer, he has a solid flow, he varies up his delivery and flow across different songs. Conceptually he has a big variety, he main focus is 'teach the truth to the youth', but he has wordplay songs, lyrical excersize songs, party songs etc.
I dont know how you can say skillwise mega is on top, his flow is shaky dog.
Artistically its a different story, and consistency wise its a different story, and i think that persona wise sai comes across as 'hollywood'...