Chin, J.P., Diehl, V.A., & Norman, K.L. (1988). [Development of an instrument measuring user satisfaction of the human-computer interface](http://portal.acm.org/citation.cfm?id=57203&dl=). CHI '88 Proceedings of the SIGCHI conference on Human factors in computing systems. 213-218.
interesting (and short) article on analyzing user satisfaction in some software. the only quote relevant to my project is on efficiency vs. satisfaction as descriptors of effective interface design:
>For many tasks, speed and accuracy are two related performance measures which affect a person's attitude toward the system. The time it takes to learn a system and the retention of acquired knowledge over time also affect the utility of a system. User acceptance of a system (i.e., subjective satisfaction) is also a critical measure of a system's success. Although a system may be evaluated favorably on every performance measure, the system may not be used very much because of the user's dissatisfaction with the system and its interface.