I gave up on the Roissy bus as they made no useful provision for luggage-it all goes on the bus, unlike AF which stows it under the bus. As a result, some passengers keep it in the aisle near them and everyone climbs over everyone else. The last Roissy bus I was on, a gal took her seat in row 1 and left her big bag in the aisle for all to circumnavigate. The driver did nothing.

I'd probably take the Roissy bus again if getting to Opera had a clear edge, but otherwise, I've found AF worth the extra Euros.