I get those emails from United too and have been curious about their service. No experience, just a word of caution from our insurance mess.
I would definitely check with your local doctors to make sure you’re in network. We switched our company from bcbs to allied 2 years ago and it has been a PITA. Saved our company like 40k in premiums but was almost useless in our small town. Our family doctor just flat out refused service to us and we had to switch offices to get our kids appointments.
We did find a new agent that got everything straightened out. I don’t think I would buy direct, insurance is so f’d up at this point you really need an agent to be able to ask questions and mediate between you and the insurance company.