Few pages behind in this thing, but I like the GGEM's blocking influence, during -AO and/or -NAOs, more so than the GFS Euro (for positioning aspects in space) and always have.   Maybe it's something to do with that index being more important/urgent in every day means up there, but just anecdotally they seem to do well with that aspect.  A blend in the ens means may be more useful.  I haven't looked at jack squat since very early yesterday morning and that was a just a cursory pass thru.