What do you think the most important difference between "IT security" and "Information Security"?

IT security is usually all related to logical access control, IT environment auditing .. everything that is related to information security in IT sense. 

It's the most important area of information security and most breaches and leaks happens usually through logical channels.

Information security is a bigger scope which includes how to secure sensitive information whether it is digital or non-digital. 

This means that information security has a broader scope which include

1- physical access

2- law adherence 

3- procedures and controls around any transactions 

for example it might be required procedure that a new hardware should be inspected for not being tampered .. another example is if you need to register physical access to enter a specific room .. even if you have a policy regarding counting users in and out of building specifically for fire incidents, auditing of paper work .. etc.

Information security is concerned about protecting confidentiality, integrity and availability of data in any format , included printed, spoken,...

while IT Security is the process of implementing  systems and controls to protect  information

IT security is the technical part, information security is more broader, and includes policies, proceedures, and guidelines among many other aspects

IT security is a subset of information security, in most instances. 

IT security is technology related whereas information security is related to information in any form even if it is stored on paper.

 Information Security is the governance of Security, typically within the context of Enterprise (business) operations. The governance of Security includes tasks such as defining policy, and aligning the overall company security strategy with the business strategy.Information Security governance solves “business level” issues and this function transcends the IT department while as IT Security is They are responsible for IT Risk Management, Security Operations, Security Engineering and Architecture, and IT Compliance.