I have iPad app with near 70 draw calls (GUI + meshes). If camera is orthographic i have 20 FPS. In perspective - 30 FPS.
Edited. More info:
Perspective camera shows more objects:
38 - 50 draw calls for orthographic camera and
63 - 75 draw calls for perspective one.
Nevertheless, app with perspective camera runs faster:
orth: 17 - 21 FPS depending on the number of objects
pers: 30 FPS stable, sometimes 28.