Wirelessly posted (Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.0) BlackBerry7100i/4.1.0 Profile/MIDP-2.0 Configuration/CLDC-1.1 VendorID/103)
I migrated from an i930 to a 7100i. The suretype is much much easier to use. With my i930 I rarely if ever sent email from my phone. Now I almost exclusively use my blackberry for email. The only thing that I think was dufficult was installing programs. It was easy with the smartphone to just drag and drop. With the blackberry it has to be done through the desktop software.
So after all that my conclusion is that I would never go back to a smartphone again. I would say the learning curve would be about 2 weeks. Hope this helps!