Hugely variable depending on aircraft type. And aircraft type is the luck of the draw.

For example, I am flying from Mumbai to Addis tomorrow night. When I booked the flight, it was supposed to be a 787. Then it was swapped to a 77L. Then to a 763. Now that OLCI is open, it is a 757.

The 787 and 777 are an international standard experience. The 767 can range from tolerable to downright awful, depending which specific airframe operates the flight. The 757s are wonderful throwbacks to how flying was in the 1980s.