In order of preference I would rate them VS, AF, CO in Y.

The VS product on the A346 is very good - excellent AVOD, reasonable food (for Y) and generally friendly crew + new aircraft. Legroom is reasonable too.

VS checkin in EWR can be a little bit slow (CO elite doesn't get you anything) but if you check in online you can use a "fast bag drop" line which saves quite a bit of time.

Lots of people on this board complain about the VS hand baggage allowance but it's a bit hit-and-miss as to whether it's enforced or not.

AF on the return has improved massively since they re-opened Terminal 2E at CDG. It involves a bus to transfer between terminals when arriving from BCN, doesn't take too long though. Pretty good AF lounges that you can access as CO plat.

AF onboard product is not too bad, depending on the aircraft there is usually AVOD, and the food (and wine) is the best out of the three. Crew are very friendly if you make a bit of an effort to speak French - even a few words.

CO international is fairly predictable. You'll get elite checkin at both ends, exit row seats (on the 752 go for row 16) but don't expect anything special with regards to service. 50/50 chance of having AVOD on the 752.

Hope this helps!