Interface design includes two aspects: interaction design and presentation design, but there have not been many works examining the effect of these two aspects on user satisfaction with the system. We conducted a comparison study analyzing user satisfaction with system features in three digital libraries: ACM Digital Library, IEEE Xplore Digital Library, and IEEE Computer Society Digital Library. Our results showed that the two interface aspects of a system: the presentation and interaction designs, may receive rather different, even opposite (positive or negative) user opinions. Weak design of the interaction aspect could possibly be compensated by a good design in interface presentation. We observed that interface presentation is no less important than the interaction aspect. Based on the findings, we suggest interface design balancing between these two aspects instead of emphasizing either one but ignoring the other.