Particle image velocimetry and planar laser-induced fluorescence techniques are used to measure the flow of scalloped, lobed, and splitter mixers. Special attention is given to the understanding of the details of the flow for the scalloped mixers and the role of the notches in enhancing the mixing process. The comparisons between the three mixers are explained by providing detailed measurements on several axial and cross-streamwise planes. Scalloped-lobed mixers enhance the mixing of the two streams by generating an additional pair of small-scale streamwise vortices not observed in the lobed mixer shear layer. Under the same test condition, the impingement of the inner flow on the mixing duct occurs further downstream than the lobed mixer. For the scalloped mixer, the decay of the cross-streamwise velocity starts at its exit plane, while for the lobed mixer, there is an initial magnitude rise before the streamwise decay.