I've noticed a change in VMFS 5.58 (that came with ESXi 5.1) against VMFS 5.54 (came with ESXi 5.0). It’s a change in the way the endSector of a VMFS partition is counted. In 5.54 it was like C*H*S-1 and it was quite obvious and easy to understand. In 5.58 it’s the number of sectors – 34 (like 17KB). I know that GPT holds a backup of the partition configuration. But if you will ever have to recreate the partition without partedUtil it can make a difference.