I like it but I can't think of it like a major track or something Genesis will be remembered by. I see it like a little thing they had fun with, better than YOSW in my book but I much prefer Steve's instrumentals on the B side. Those are imo quite underrated.
I heard Phil's big band perform it in the late nineties, as arranged by Brad Cole, and I think the tune found its perfect medium there. Forgive me, but when you say "b side" do you mean side two of W&W? If so, then Blood On The Rooftops is, for me, the song for which Hackett should be best remembered. People may rave about Firth Of Fifth (poor Steve sounds like he's suffering from arthritis during that much celebrated solo) but that was Tony's song; Rooftops is the perfect balance between Steve and Phil and is a work of absolute genius.