We just flew to LHR from BOS in Delta One and back in Upper Class. Both A330.

Catering on DL was horrendous, quite simply the worse on any Delta long haul flight in any class of travel since the NW merger 10 years ago. The food on VS was better by default.

The seat is overall better on DL than VS, but there were some technical issues with audio and AC.

The level of service was significantly more friendly on VS.

That said, I’m chalking the experience up to one off poor catering and a surly crew that was not what I normally experience on DL. It’s my first longhaul flight in a year, so I’m not sure if there has generally been a decline of service quality in Delta One in recent months.

if you want a great seat to sleep in with few expectations beyond that, definitely fly Delta