Accept offer or continue in EY GDS

Hi all, I am currently working as a SCon in EY GDS, YOE - 6.5, Current CTC- 15 Lpa, I recently got an offer from Amex for band 30 at CTC 21 LPA...In EY my increment is due next month and I have completed 1.5yrs here...should I wait for sometime then switch or accept offer from Amex? Pls advise