Legacy UA FA work rules aren't better than CO's if you are looking to maximize your income, as many CO FAs do. Even though legacy UA had significantly more long domestic and international routes, their flight attendants made/make significantly less than Continental people because United workrules limit their ability to work as much as they can.

A midlevel-to-senior sub-CO FA can clear over $80,000/year in annual income if they work hard with a good mix of longhaul and domestic. Sub-UA FAs struggle to go much past $50K because a combination of workrules and surplus employees limits their flying potential.