SLF, "I've always thought that airlines are more likely to upgrade their own nationals."
I would agree with that. When I went out to MUC, knowing that I was going to be there for 18 months, I had to decide whether it was going to be BA or LH. I chose LH as I was irritated by BA.
In the end, about 90% of the trips were on LH, a few on BA (price/time/usual reasons) and two trips on GO. I also had one - but one only! - trip with DebonAir .....
Overall, I had no complaints and used the mileage last year to go LHR ~ MUC ~ JNB return in C, so that was OK.