Have you tried the VS non-787 products?

I've flown both A339 and A350-1000 products recently out of JFK and they were both nice from a hard product perspective. At JFK, you'll have access to both the Delta One lounge (very nice, if not busy) and the VS Clubhouse (middle-of-the-road but peaceful). At LHR, VS has great ground service with the private check-in and security, not to mention a wonderful lounge experience.

In-flight service/food is "meh" IMO, but it's such a quick flight (by TATL standards) that it doesn't bother me much.