It is completely based on your core interests. Both institutes are well renowned. The EE program at IIT Mandi will help you improve your potential using the resourceful classes offered here.
IIT Mandi guarantees the best placement support. Usually, the students prefer CSC rather than EE, but when we look into the curriculum of EE, it has a significant part in electronic studies.
Other than this, the most significant feature of IIT Mandi is its branch change policy. Most of the students prefer a branch change after the first year. You can also be a part of it if you have an interest in coding and software. So, you can opt for IIT Mandi based on your interest in the core subject.