All fields are equally good and have a lot of opportunity. It depends on your interest and aptitude. There are fields beyond MBBS and Engineering that have gpod scope too.

Since you have limited yourself to these two I will say that both have their own advantages.

Engineering is just a 4 years course after which you can apply for a job or go for even higher studies. Engineers after UG often change their field of interest. Work is not as stressful as a doctor.

Getting an MBBS degree itself will take you 5.5 years and then you have to do MD/MS since there is little scope for just an MBBS doctor.  After this long period of hardship the work environment too requires a lot of energy and time but the profession is much in demand and very respected .