If you were to fly between LHR and US East coast, what airline would you choose?

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.