My experience is that there is more interflight variability within individual airlines than between different airlines. That said, here is my ranking of itinerary alternatives (not airlines).
1. Fly direct (always saves several hours and worry about misconnections).
2. If connecting, make your first flight the trans-Atlantic one, and the second one a US domestic or intra-European one. This is because if you misconnect, there are many more domestic US or intra-European options to complete your journey than there are trans-Atlantic ones. Thus, your incremental delay is more likely not to exceed a couple of hours -- rather than a half or whole day as could be the case with a missed trans-Atlantic flight.