I found BA quite good and very cooperative. I was flying Chicago-London-Mumbai and my transit time at London was only 40 mins. My flight from Chicago was 25 min late, to my surprize they had special arrangements for me and my luggage when I landed at Hethrow. A seperate fast security check lane helped me clear security in marely 3 mins and my next flight was waiting for me and few others like me. At mumbai I got all my luggage too.
