Disclaimer: I had pursued MS Ophthalmology and had not written the DNB entrance exam during my pre-PG time.
A few years back I would have told MS/MD is better than DNB for the simple reason that the selection process for DNB was highly suspect. You getting into a DNB program depended on the right kind of people you knew or on the mercy of the institute you were working as a medical officer. It wasn’t at all fair. There was no credibility for the doctor getting in. Also pass percentage was extremely low…in ortho and radio it was less than 10% pass rate. the centers never bothered about results hence no academics
But things have changed since 2010. There is an All India DNB entrance exam and a central counselling process for both primary and secondary DNB which now adds credibility to the course and now pass rates are approaching 100% in most centers as institutes realize only having slave labour won’t cut it and they will have high attrition rates if they don’t invest energy into academics and teaching.