I know this much. Despite the huge amount of traffic in UK and Europe it’s still the safest airspace I use. The Far East, especially India is a nightmare closely followed by Syria and the Cyprus mess. Even China has improved beyond all recognition. The French as ever are a law unto themselves, it just amazes me how they have managed to avoid a serious accident attributed directly to there complete disregard of ATC language rules. I was sat at the hold in Paris a couple of days ago surrounded by French registered aircraft and hadn’t got a clue about what was going on. There all chattering away in French. When are these guys going to grow up. It would be interesting to hear from French ATC on this forum!!! If they dare.