According to the results of the meta-analysis by Nielsen and Levy (1994), there is a strong positive association between user task performance and subjective satisfaction. Inconsistent with the findings of Nielsen and Levy (1994), the main finding in the current study (based on the results of the correlation and RM-ANOVA analyses) is that outstanding task performance does not always guarantee a high level of user satisfaction, as suggested by the weak positive relationship between the two variables. In fact, both the fingertip and rubber-tipped stylus, which were faster than the acrylic-tipped stylus, resulted in outstanding performance; there was no significant difference between these two input devices in terms of task performance. However, compared to the rubber-tipped stylus, the finger had a low level of user satisfaction. In terms of display, the elastic display was outstanding in task performance compared to glass, but no significant difference was found in user satisfaction. In general, most smartphone or tablet users are familiar with various styli due to exposure via news articles, hands-on experience in the store, or prior experience with other typical styli; however, the soft-surface touchscreen used in this study might have been less familiar than the styli. Moreover, the novelty of the soft touchscreen might lead to an increase in uncertainty about the product quality. Accordingly, designers should make an effort to consider both the relationship between perceived familiarity and novelty as well as the relationship between user task performance and subjective satisfaction in the interaction design process, thereby handling the conflict between them.