Mobile services hold a promise of utilizing the phone also for other purposes than purely communication. However, repeated attempts at realizing mobile services in the market place have been met with limited success. This article (1) defines the architectural drivers that drive success or failure of mobile services, (2) analyzes three different architectural styles of realizing such a mobile service using the example of a movie ticket selling service and (3) presents the results of this analysis. The main result of the analysis is that a serious conflict exists between usability and essentially all the other architectural drivers included in our analysis, i.e. portability, deployability and scalability. This is due to the fact that, because of the restricted state of the art technology, only native client applications offer satisfactory usability, but these do not satisfy the other drivers.