I currently have Kaiser, but am offered a health insurance through United Health PPO. What would you pick?

I currently have Kaiser Personal advantage and can get United Health Care PPO through my company. I don't know whether I should stop my Kaiser insurance and sign up for the United Health Care PPO, or just stay with Kaiser and not sign up for the company's health insurance. I don't even know if it is good to have both, I'm not sure if this works or not. What do you think? Any advice is appreciated, thanks for your help.
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united health care ppo is good
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