Personally, Vueling is my preferred poison. I've had an early morning 6:55 flight out of CDG without any issues but I usually arrive early anyway. BCN might be different due to the size of their operation there but shouldn't be a factor unless you need to check bags or check in with an agent. Might want to consider if either airline has any frequency advantage on the route you are considering in case something happens to your scheduled flight. It's probably a toss up.