Also what are the benefits of having these account managers?
They're useful as a point of blame if something is going wrong. I find it better to tell people "I've called Jane and she's looking into it" rather than "I've emailed support and am waiting to hear back".
They can enable hidden features that aren't generally available.
They typically get a faster response back from engineering than the general support line. That said, I get an even faster response generally by waving my arms and yelling on WebmasterWorld. ;-) Bad Moderator! WebmasterWorld is not the AdWords support forum!
Anti-Benefit: They are typically harder to get on the phone than the general support line (and no, you aren't reading that wrong).
I find them able to expedite clickfraud issues.
They provide me with advance notification of features.
They tend to be more helpful and self-starting than the general support line.
You tend not to be poached by Google directly if you have an account rep and are involved in an MCC relationship.
Overall, it's nicer to have an account rep than not. Still, there is a lot of room for improvement. I still feel like a customer, not a client. That's the pitfalls of self-serve advertising, I guess. I spending a salary on someone to manage my campaigns, that's a salary less I could be spending on advertising.
What I cannot stand is how 'cheery' they are told to be. They are told to act like are 'mothering' you and always so polite...but usually not very helpful. I could never be one of them.
I have used my reps for a variety of things: Spreadsheet uploads for building new campaigns, having them build new campaigns when they come up with new ideas for increasing traffic, for solving minor and major problems and just for getting more in-depth information about certain aspects of Google that I need help with. I had one rep that was great for brainstorming with me...we would talk on the phone and throw various ideas around about how to improve the account. Sometimes she would see things that should have been obvious to me but because I had been in and out of the account a million times...I just wasn't seeing it.