Hi
sani15, your post does not explicitly indicate whether you're looking for
online classes or
classroom coaching. So, I will cover
that aspect as well.
Online classes offer benefits such as flexibility of time and ability to pace yourself.
Classroom coaching on the other hand, requires students to travel and mandates that they present themselves at specified dates/times for the classes.
This obligation to be present at specified dates/times for the classes can actually be a
blessing, for it imposes the much needed discipline required to ace GMAT.
My suggestion would be that before finalizing, make sure that you attend free
trial classes with at least few institutes (both online and offline), so that you are comfortable with the instructors and the medium of instruction.
The various aspects of coaching that matter, include the classes themselves, the quality of instructors, the support provided by the institute outside of the classes, and the quality of study material.