What is the best framework for IT governance? Is COBIT 5 considered the best for time being?

yes COBIT5 is the comprehensive governance frame work and it is integrated with

ITIL, ISO20000(ITSM), ISO27000(Infosec), Enterprise architecture, Basel III (Banking compliane,   PCI DSS (Data card security standard), Coso, ...

yes it is.

however the work needed to adapt teh process to your organization needs a lot of work.

cobit is like raw potato...and you will ahve to peel, fry and cook it to make teh perfect chips with teh flavor you need for your company.

Reading and understanding ITIL will help as it has some elements of governance in it too.

Yes, COBIT5 is the best IT Governance framework. COBIT basically answers the "What should be done for IT processes, standards, policies." But to supplement additional questions like How, When, Where, you require additional standards and best practices supplied by other frameworks such as ITIL, TOGAF, ISO, etc.