Which one of these would you guys use in a new PVS environment.  Both seem to have the same advantages vs DHCP options but wanted to hear from folks with operational experience.  I am having a hard time finding any downsides/gotchas to partitions.

In my experience i've always preferred the ISO method. Less steps and provides redundancy (provided all the steps are followed. That said, not saying partition isn't a worthwhile option but can say ISO's been rock solid for me. George does a good breakdown - https://www.jgspiers.com/citrix-pvs-boot-device-manager/