My experience of Lufthansa was on a trip to Turkey. Both legs involved a changeover in Germany, at Frankfurt and Munich respectively.

My overall impression was pretty good. Historically I have flown Turkish Airlines and BA on these routes, and I would certainly consider this route again even though it is not direct.

The aeroplanes themselves were clean and neat inside, although it looked from the outside of the plane as if it had been around a while it shows they have spent money keeping them in decent condition. The staff were friendly and efficient. The inflight food was alright, apart from the sandwiches which were very dry (quite typical of German ones to be honest). Legroom was no worse than the other airlines.

The changeovers in Germany were pleasant and hassle-free, so although it lengthens the trip the cost saving made it a decent trade-off. Both airports were modern, with enough space and facilities for everyone and more besides. Flights were on time and boarding smooth.

My main disappointment came right at the beginning of the trip. They had an automatic check-in that was meant to scan passports and issue boarding passes. This totally failed to work, printed out once boarding pass and then displayed error messages. The one staff member present was attending to someone else so I had to wait around for a while to get it fixed, which was quite a stressful experience.

So in summary, I would fly Turkish Airlines by preference (new planes), then Lufthansa (decent but not direct), but would avoid BA at all costs (appalling customer service ethos).