Final answer:
The Salesforce Community feature allows external customers to view and interact with their open cases, fulfilling the requirement of SFB Industries' high value customer. It is the most suitable solution compared to Email to Case, Case Comments, or Salesforce Answers for sharing case information with external users.
Step-by-step explanation:
To enable a high value customer of SFB Industries to view all open cases and add comments, Salesforce Community should be utilized. This feature allows external customers to see their open cases and interact with them, such as adding comments. To set this up, you would typically need to enable a community in the Salesforce Org, configure the necessary case sharing and visibility settings, and then provide the customer with access to the community.
Here are the functions of the other listed features: Email to Case allows cases to be created from emails sent to a specific email address. Case Comments let users within the Salesforce org add comments to cases. Salesforce Answers is a feature used mostly for knowledge articles and question-and-answer type of interactions among users, not specifically for case management. Therefore, out of the options provided, Salesforce Community is the best fit for the customer's need described in the question.