If you rename a spawn egg (eg bob) and then spawn the mob, it will not display the name of the mob like a nametag, and if you do: /testfor @e[name="bob"] , it will not detect the mob, but if you rename it with a nametag it will display the name and if you run the same command it will!

It would be great if it was able to detect the mob from the spawnegg name, and also would be consistent with java edition!