Although the "Career Manager" designation sounds pretty good, they have a lot of people to look after, and the Forces needs will always supercede your own needs. Mostly, you go where he tells you to go (postings). Don't expect him to overly caring about you, and don't try to flash the "If you don't post me there, I'm getting out" type of thing, or you could very well be handed out VR papers...
I seen that first hand, and the poor fellow was out before he could realize it.
If you're lucky, you get to see him once a year for a 15 minutes interview. He looks at your MPRR info (make sure it's updated), and tells you if you're posted or not this year ,if you're getting promoted ,if you're getting course loaded on the next career course. I find that to have access to his online briefing before you see him is the way to go. Then, you know how many people are being looked at on the merit board, and how may expected promotions.
My 2 cents...