On the Earth Simulator, there are/were several application codes which are using one-sided communication (instead of 2-sided). They used one-sided communication especially to overlap communication and computation. When I remember correctly, at least one of this applications won a Gordon Bell Award of SC.

The ambiguity of the progress rule notwithstanding, there is no particular reason that one-sided should give you better overlap than two-sided. If this is the reason that people use one-sided, maybe we should revisit the progress rule ;-) Keith