eBGP Graceful-Restart and GR Helper Mode with external networks.

Is there a BCOP (or substantiated opinion) for negotiating eBGP Graceful-Restart and Graceful-Restart Helper-Mode with external networks? Implementation looks varied across a few larger transit providers, and in some cases implemented inconsistently within the same provider. Seeing most IX peers with GR disabled, although I don't see they've disabled GR Helper Mode. Apparently, Junos (12.3, at least) doesn't offer disabling GR Helper Mode for BGP. Thanks.