The upcoming of smart phones are the result of consumers' preference for high-feature products: manufacturers are lured into integration of a growing number of technologies and features to provide attractive and competitive models. At the same time usability of such complex products becomes an increasing problem. This study aims to provide designers more insight into the consequences of emerging technologies on the usability of smart phones with different platforms. We conducted a usability benchmark study and tested 4 different features on 3 smart phones with 3 different platforms (Nokia E6li (Symbian S60, cell phone type platform), HTC S710 (Windows Mobile 6, PC type platform), Palm Treo680 (Palm OS, PDA type platform)) with in total 43 s...