Delta Airlines:
I recently flew Delta One for Heathrow to NYC, and it was very good (check out my full review). But I have to say that the difference between the crew on the way there and back were very different. On the way there, the crew was very warm and attentive throughout. I didn't feel the same on the way back. The crew was a lot younger and less experienced on the way back. I also feel like Delta need to standardise there business class offering on there long haul/mid haul flights. They have different products on the 767 and A330s which can be quite confusing.
Due to the coronavirus, Delta is sending their transpacific brand new A330neo fleet over to Europe for transatlantic route, it will add even more confusion on onboard product. But I have to say, Delta is keeping their fleet very tidy and refreshing, even with their B767 fleet. I start to like them as well!