While sketching in a part/assembly, it is annoying when dimensioning to have to either project geometry in order to create dimensions or have the application option of auto-projecting geometry in sketches turned on (which creates performance problems in large assemblies because of all the projected geometry). An excellent feature in inventor would be to allow users to dimension to existing edges of a part/assembly without having to project geometry (like in Solidworks). At the very least it would create projected geometry automatically while dimensioning (so that when you select an existing edge to dimension to it creates projected geometry on only that edge automatically).