It is not so much a choice of which to use, it will be determined for you due to bore wear, as to whihc size is needed, ie a re ring with the pistons that are in it at the moment, or if bores are worn, then a rebore with the next size up pistons/rings.
The advantage of lower compression pistons is if you want to run a LOT more power, with lower CR you can boost a lot harder.
tabetha