Full Time MBA

Hello,
I am assuming by open you mean MBA through correspondence.
The difference as the name suggests is in the mode of study, both are designed for different sections of people and both are relevant looking at the cause for which MBA is being done
Regular courses are classroom session courses where students have to attend classes; this is nothing but full-time MBA which requires your complete commitment for two years. This is the most preferred by recruiters and organisations.
Distance/correspondence courses are more about the self study where the study material is sent to the student and they have to understand and learn it on their own. The main advantage of this is fees is low as compared to executive and full time. In distance MBA, you'll have classes once or twice during the weekends, and you'll have exams twice a year.
Regular MBA is much better without any second thought-if you have an option to consider and your situation allows to.
The exposure that you get in any regular classroom, the interaction with the faculty members, the networking with your peers and colleagues is unmatched.Correspondence will never be able to fetch you even a small percentage of this. The regular classrooms groom a character and add value to one's personality besides just the curriculum.
Also, when it comes to the realization of these degrees, a regular course is always valued and preferred over a correspondence, whether you seek a work opportunity or a higher degree. Further, most of the organizations, while employing clearly states in their eligibility criteria that the candidate should be a regular MBA/PGDM and no correspondence is considered.
Good luck.