Sorry, I might be a bit late to the thread.
I use OG extensively for drawing my Data Models. For large assignments, of course I use heavy duty software which connects directly to the db server, but the diagrams are poor. So for many years now, for any small to medium assignment, or to elevate the quality of boring diagrams on a large assignment, I use OG. if you use the File/Export facility to produce a PDF; and the Properties/Action to JumpElsewhere in the doc, you can create quite large and complex models. Here is an example of a 4-page
Data Model, with links (click the blue glass buttons or shadowed or collapsed objects).
I do not understand why people use all sorts of different diagramming techniques with various symbols, when there is a stongly established standard, IDEF1X, which most customers want, so I draw only standard-compliant Data Models. The idea is, the diagrams are complete and convey all important info.
I developed a series of Stencils of OG, posted them at Graffletopia, and received good reports. And yes, I keep them up-to-date. Please read the intro/description on each of them (saves me typing here):
Data Model (IDEF1X)
Entity Relation Diagram (ERD)
Data Flow Diagram (SSADM)
I am working on a IDEF0 (Process) stencil.