The difference between bizXpress and SBI! for WP is a great question. There are actually three areas in which there are major differences between the two products.
While bizXpress users were given access to the same Action Guide that SBI! users refer to, SBI! for WP users now have a completely new Action Guide that has been updated and tailored specifically for WordPress users. It has also been structured similar to most online courses, complete with modules and units, quizzes and completion status. We think you’ll find the new Action Guide to be more applicable to your needs and easier to digest.
While bizXpress users were given access to the same premium content that SBI! users rely on to grow their business, SBI! for WP users now have their own extensive collection of articles, tips and techniques exclusively for WordPress users.
Finally, while the original bizXpress plugin provided easy access to the Action Guide and external tools within your WordPress implementation, the new SBI! for WP plugin does much, much more.
First, your entire Master Keyword List is synced with your WordPress site so that you can target any of your chosen keywords on a specific page or post.
Second, when you select a keyword from your MKL (or add one on the fly), you’ll be able to see that keyword’s usage data right there, without having to leave your site.
Third, with a keyword selected, you will be able to see which other posts or pages within your site you’ve targeted that keyword on.
Fourth, you will be able to call up valuable competitive insights, including links to current ranking sites, associated with your targeted keyword.
Not just within your WordPress site, but while you’re actually in the midst of writing or editing a post or page, so that you can make sure that the content you’re providing is what your audience is actually interested in.
I think you’ll agree when we say that SBI! for WP is an incredible improvement, and a huge competitive advantage for any business to have access to.
Try it. Simply follow the Action Guide. 
No strings. Better, actually...