It all depends on what interests you. Mechanical is for you if you are interested in automobiles, machines, fluid mechanics, and other stuff. Electronics and Communication is for you if you are interested in electronic, communication engineering, mobile and wireless communication, and how electronic devices work.
As an Electronics and Communication Engineer, I would not be biased in favor of the subject. However, Electronics and Communication is closely linked to Computer Science and involves programming and embedded system development. However, Electronics is a promising field due to the rapid development of Artificial Intelligence, Machine Learning, and Automation. All of these technologies use Electronics, Communication, and Signal Processing as their core. The exponential growth of machine, automobile, bridges, and truss development in Mechanical makes it equally promising as we move towards the spark that will ignite technology in the 21st century.