Beware that United charges $425 for an oversized + overweight bag. Southwest will charge $75 for the exact same bag.

Story:
Checked a bag which I knew was oversize +$200 and weighed 71.5 pounds + $200 for a total of $425... That's a huge difference compared to Southwest where 2 bags are free and oversize/overweight is assessed only once, eg the same bag cost me $75 on the outbound and $425 on the return.

Tried pleading with the agent to give me $325 since it's only 1.5 pounds over 50-70 pounds but no go either...

Anyway, be warned about this additional hidden charge on United/AA vs Southwest.