I just started my geometry class on triangle bisectors. Today we walked a movie where the instructor actually showed students where the names for the circumcenter and incenter come from and showed them both the angle bisectors and perpendicular bisectors. For the last few minutes of class I had students play with the geopad app but a few decided to play with geoboard. I looked at both apps but only the geopad will allow students to create the triangles, put the appropriate bisector on it and place the circles around the various triangles. Furthermore, it allows students to move shapes around so they can observe for themselves what happens to the points of concurrency with the various type of triangles.
On the other hand, the geoboard app allows the students to create large triangles in a much easier manner. They can use a rubberband to make the bisectors but they may not be able to make the bisector perfectly perpendicular or cut the angle precisely in half. The geopad has an option for that. In addition, geoboard will not allow students to add a circle. I do see geoboard as being the better choice for tesselations, transformations, shapes. All told, I think each is good for certain circumstances.