You need to unsterstand that there are two BAs
#1 - the airline
#2 - the business
In my experience as a frequent traveller, BA are well above the average, on the ground and in the air, for service.
There's always the matter of chemistry between individuals, but generally I have a good experience.
I've never been treated like I was by Air France at CDG the other week, when flying to Rome - the very stroppy check in agent didn't want to be there and had a row with her supervisor about her break times in front of me .... very professional #1 - I suppose they assumed that I couldn't speak French - very professional #2 and then the agent checked my bags through to the final destination without telling me, despite it being self evident that I was nightstopping (arriving at 21:30 departing at 13:30 the next day) - very professional #3
On the other hand, there is the BA business which suffers from the Peter principle as much as anyone.