IIT Roorkee Mechanical will be better. It has an excellent placement record. IIT Roorkee Mechanical average package is INR 15 LPA. Reputed companies like Google, Microsoft, and Maruti Suzuki recruit from the branch. You can also get good placement opportunities in the IT sector.
IIT Roorkee has various clubs such as Web development Club, Programming Club, Robotics, etc. If you are interested, you can join any of these clubs and build additional skills.
Let’s talk about IIT Roorkee Mechanical branch first, it’s a good college with great faculty, good infrastructure. It was ranked at AIR 6th in engineering institute in India 2019 by MHRD. Most of the learning in mechanical engineering (approx. 95%) is done via peer learning and rest come from academia and to support that the institute have the best crowd of competent, intelligent and hardworking minds of India. It has one of the best alumni network which is supportive and helpful. Placements is good in core as well as in other industries. In 2019 the median CTC offered at this institute was 10 LPA.
IIT BHU Electronics branch has a good course structure and it is among the few IITs offering branch specific courses in the very first year. The institute also has good infrastructure with modern labs and equipment. Faculties are not in par with other IITs but you will have guidance from your seniors. Placement is good with average around 13.5 lakhs per annum and placement rate is around 80-90%, few core companies which visit for placements are Bharat Electronics Limited(BEL), Qualcomm, Samsung Electronics, Toshiba, Philips, etc.
Final verdict, whichever you take, is totally up to you and there are ample opportunities in both institutes.