Bigger brand name where the coach was coaching for his life the last two years.
The Coaching profession is a pretty nomadic lifestyle if you are an assistant. Some guys will attach themselves to a head coach and try to ride that relationship as long as possible- either for professional or family reasons. But it is much more common for assistant coaches to job hop to gain knowledge and develop connections to rise up the ranks.
Berry isn't only interacting with Shaka in hope to someday become a head coach- he is also working with different assistant coaches and a different AD. Having a lot of relationships can only help. The Texas brand name also won't hurt Berry. He will also develop recruiting connections in the state of Texas which produces a ton of HS D1 recruits.