Q : Does it turn corners? Does it work on corner / bowl front tanks?

MOAI doesn't cross corner. 

Q : Does it cause sand storm / sand stuck / grab sand / scratch glass?

No worries. MOAI has a navigation system.You can set cleaning area above sand bed with mobile app.

Q : How long does the battery last?

With a full charge, MOAI will clean up to 90 minutes.

Q : Is it able to avoid frag racks and power heads?

MOAI can't avoid obstacles like frag racks and power heads. The clearance between glass and obstacles should exceed the thickness of wet side ( MOAI: 17mm, MOAI +: 22mm).