You mention EU261. The scheme applies to EU carriers on flights from and to the EU. The non-EU carrier is only covered on the flight from the EU. On your return it does not apply.
I live in the UK. My nearest airports are places like Exeter and Bristol. However, I choose to make my way to Heathrow and even Gatwick for long-haul. Why? Because it means I can fly non-stop. From any of the other airports round here I have to change somewhere. Actually, I'll even go to London for most short haul mainly because of flight frequency.
How do I choose airlines? I think the first thing to say is that I'll fly in almost anything, anywhere. Yes, the risk on a Nepalese Twin Otter into the Himalayas or a CAAC IL14 may be higher than on a BA 747 on Air Canada 777 but when the alternative is the driving habits in some countries I'll fly! That said, I have a very personal way of choosing which airlines to fly on based on safety, comfort, occasionally aircraft type and (some) loyalty. Price usually comes at the bottom of the list!