One drawback of going to OGDCL is that I am currently working in EG3 at SNGPL and will be eligible for promotion to EG4 next year. On the other hand I am being offered EG2 in OGDCL and their parking period in one grade is 5 years which is more than the parking period in one grade of SNGPL (i.e 3 years). So it seems that promotions in ogdcl are slower than Sngpl.