  Hybrid visualizations mix different metaphors in a single layout of a
network. In particular, the popular NodeTrix model, introduced by Henry,
Fekete, and McGuffin in 2007, combines node-link diagrams and matrix-based
representations to support the analysis of real-world networks that are
globally sparse but locally dense. That idea inspired a series of works,
proposing variants or alternatives to NodeTrix. We present a user study that
compares the classical node-link model and three hybrid visualization models
designed to work on the same types of networks. The results of our study
provide interesting indications about advantages/drawbacks of the considered
models on performing classical tasks of analysis. At the same time, our
experiment has some limitations and opens up to further research on the
subject.
