What is the difference b/w a master's degree by coursework and a Master's degree by research in terms opportunities gained after completion?

Coursework degree will have more practical experience and exposure and attract more options

The coursework master's is best for those who have limited or no prior preparation in the subject. This way they get the broadest exposure to the subject. For those who have a strong undergrad preparation already, the research option is better because it exposes them to something very different and also very valuable (even in industry). Of course, there's no reason someone without a strong upgrade can't do research—it can be very rewarding for them, too. But they have more of a breadth vs. depth trade-off to make. There's less trading in the other cases. That's in terms of value. In terms of opportunity, it depends on the kind of job you want (though your experience may also slightly affect what you can apply for). The research experience—assuming you did actual research, and did it well—will definitely open up a few more doors that would otherwise have gone only to PhD students or extremely motivated, competent self-taught individuals. Too many factors determine how many such doors to provide a useful generic answer. However, in general, employers are not expecting much research out of a master's student. Therefore, they probably are not making a big distinction here. As a result, you are best off picking the thing that gives you most value. Personally, I would suggest that if you have the opportunity, do some real research. It gives you entirely new skills, ones that I think will serve you well over a very long term.