Thanks for the comments!

The Form builder is designed to handle line-of-business forms that have some kind of approval process and role-based access. If you want to recreate Word doc look & feel, the major limitation we have is that you can't nest table layouts (yet). The good news is that most business forms are pretty 2 dimensional and you can normally flatten out the tables. You have to play around with row and column spanning to get the look you need.

One of the major limitations of Word documents we sought to overcome was the many-to-one problem. With a Word document, there is no easy way to repeat groups of fields. The Form builder has support for editable many-to-one relationships, with role-based security. (This lets you control who can add/delete child objects)

With this VWG form designer, you get a Web-based form editor plus AJAX-based instant responses in the document. It's not an accident that the Forms/Sections/Fields architecture map exactly into an Excel workbook.. this lets us harness an Excel formula engine and get instant responses to cell changes. It also lets us refer to cells in a very familiar way, since the target form designer will likely be a power-user that knows Excel.

As for a replace for Sharepoint Excel Server: I think this offers some advanatages if you take the time to recreate your workbook in the tool. I don't have an Excel importer feature (yet), so it's a little laborious recreating each worksheet. However, one major advantage we have is role-based access at the cell level. That is quite difficult to do with a standard Excel workbook since there are no built-in roles per se. We can also hide data based on roles and other business rules.  

Sorry for long response...I don't want to mis-represent the capabilities..

Mitch