Nextel customers and BlackBerry users are two staunchly dedicated groups of people, which is why it came as no shock to us that theRIM BlackBerry 7510, offered by Nextel, met with a good amount of enthusiasm. Finally, Nextel users who loved the company's business-oriented Direct Connect walkie-talkie service could join the BlackBerry craze. Of course, like early prototypes, the 7510 had some limitations--namely, a paltry 16MB of memory and no Bluetooth. Fortunately, the RIM BlackBerry 7520 answers these criticisms with 32MB of memory and Bluetooth capabilities for wireless headsets, earpieces, and car kits.