Live reporting from CX879 right now (SFO-HKG). Currently flying right over the Pacific (taking a rather southerly, very much non-polar route). This is what my $20 full flight pass gets me (pre J/DM roll-out):

I still find it a wonder of technological progress to be able to do this at all, though I can't imagine what happens when corporate 'elevates' this without adding actual bandwidth...

edit: this is an A359 so probably older gen Panasonic WiFi