I have two SDE (10.3.1) connections. One is View and the other is named Read. They share the same exact properties in MS SQL 2014 Enterprise. They both can connect to the database as read only users. Unfortunately only View can actually see the feature classes, and other related content in the DB. The Read user can connect to the DB but the feature classes and related content are not present (blank space in ArcCatalog). The view appears blank in ArcCatalog. I have reviewed the security setting in MS SQL Management Studio and the two users appear to be exactly the same.