GATE and IES, are very well known among graduate engineers. The IES exam is carried out annually by the Union Public Service Commission (UPSC) and the GATE exam is administered by Bangalore's Indian Institute of Science (IISc) or any of the seven IITs.
Syllabus and paper pattern:
Difficulty Level & Duration:
It will be much more difficult to solve the questions you will face in GATE than in IES.
Category of PSUs and Job Scope:
From the above-mentioned factual information, the difference between the two should be clear. Rest all depends on your choice what you opt for.