I use the Graphire, and found no learning curve whatever. I use it for all applications. Within any application, there are some things more easily done with the stylus and others with the mouse. I am not really even particularly conscious of switching back and forth, it has become so natural - just grab for the one that works best for the task of the moment.
I have never felt a need for an Intuos - it seems to have its main market among those with either full time users of Painter or those with very deep pockets. An artist friend tells me that Painter and Intuos are the perfect marriage. However, with Photoshop, 3-D applications, music, web and e-mail, video and all the rest, the Graphire meets all my needs admirably. I might add that of all my applications, Paint Shop Pro has the greatest support and utilization.