The difference of $5,000 compensation should not be a factor when you consider your move. It is not much after tax.
The primary considration is which will provide a better career for you. If a). B can provide a career path to IT manager, and b). you perfer to being a manager than an engineer, and c) you honestly think you have the skills to be be a better IT manager than an engineer, then B is the choice. Since you mentioned you didn't know much about the career path in B, you need to do some research.
The job responsibilities in B sounds more like for build and release engineers. It requires coding, but not much. If you are a good developer, it is a downgrade to be a release engineer. (No offense to release engineers.) If your jobs are primarily to manage IT products, that is, you are primarily a member of IT department, not engineering department, you need to think if you want to be an IT engineer, or an IT manager in the future. Also think what is the future for these IT stuffs.
Another option. If you want to be a developer/software engineer, think if B provides the opportunity for you to transfer to engineering team.
