The chat starts out as a bot, but pretty quickly becomes real human agent if you ask. You will know it's a real person if you see a name (e.g. "Jane D") attached to the conversation.

I've used a few times on UA or AA, mostly when I don't feel like getting on the phone and/or a phone call would be disruptive to those around me. It should be noted that chat gives you access to Reservations during flight (assuming inflight wifi works)--this could be *extremely* valuable during IRROPS.

I find the chat agents' level of competence fine, but I get the sense some of them aren't too well-versed in complex issues, such as dealing with partners or the more arcane parts of the MileagePlus program.

They can sometimes take a while to respond. One annoying UX issue is that, if I am waiting for them to go research or do something, united.com can auto log-out. Logging back in typically refreshes the conversation, but on my last chat I couldn't do this. Fortunately we were almost finished up but this could be dangerous if you're not looking.

Overall, I like that the option exists, but I would still prefer to give UA a call if I'm dealing with something complex.