You are not supposed to choose the "Best Branch" You are supposed to choose the "Right Branch"
Now let me elaborate. What factors should influence your selection of an Engineering branch?
1. Scope (future scope, not current) Every engineering has scope, now the statement is true for world level statistics (not country level) one country may have largest chemical plants, other may have energy sectors. No engineering is dying, as the number of consumers increase, there has to be a continuous demand for energy and other utilities
2. Salary: Depends on profile mostly (not the branch you graduate with), so the specialization pays you, not your major.
3. Working environment (group of people, gender, country, office or industry)
4. Belonging to a major group like Computers, Electronics, Electrical, Instrumentation, Communications, Mechanical, Chemical, Production, Construction or Industry specific groups ( Information technology, Bio medical, Automobile) for an example, Chemical Engineering is a more wider discipline than petrochemical (more trade specific, industry specific) , hence can land you more jobs, But if something assures you about taking that niche (small group) well you can go ahead.
5. Interest vs Aptitude vs Scope: There is no clear indication as to which wins over what? You like Automobile Engineering, Your aptitude wont allow, still however you manage to complete but then, short of skills in a highly competitive environment would let you down.
6. Ease of study vs Niche category vs High paying environment.
Some new trends are coming up and will be coming as a part of continuous innovation, thus irrespective (almost) of your major, you can get into biotech, or nano tech, or robotics or automation, so you major with an easy subject (easy means the ones you like, rather than subjecting yourself to the branch that has scope and you land up stressed and lost at the end of the day, everyday) and these niche paths welcome you, again to a high paying environment, even you don't have to be an IT major to get into IT or ITES
7. Engineers as freshers in most companies are accessed as per basic analytical skills, because Engineering is a Science, Industry is the real Application.

All the very best!!!

Source --> Quora :)