One of our clients was testing Toad Data Modeler to see if it would suffice as a replacement for CA ERWin to construct a dimensional model - the verdict is in, and it's "No." Toad Data Modeler does regular ER diagrams not not a dimensional model. Looks like CA ERWin is going to be the tool of choice for this client as well as many of our other clients.
Speaking of Toad for SQL Server, I'm not convinced there is a need for the product as SSMS is such a great tool. Microsoft really is sitting in a sweet spot right now by providing SSMS with the SQL Server license. Toad for Oracle is a necessity with the Oracle products.