For anyone who has experience as a Career Counselor (79S), what did you think of it and what were the day-to-day duties like?

This is the very best job in the army. I have had several jobs, and worked in conventional Army, Special Operations, and the reserve component. I have had a broad experience of the army, and almost every career counselor will tell you that this is the very best job in the army.
If you feel not your strong suit selling ice to Eskimos, then you maybe more suitable to recruiting.

Your day to day duties are that you talk to Soldiers and counsel them. Writing reenlistment contracts is about 10% of your work. There is a lot of processing actions and overlap with S1. You are your own boss and time manager. Sometimes you're overwhelmed and others you can go home at 1500 all week. You don't have any Soldiers but you're essentially the problem solver for the whole battalion.

Let me tag resident Career Counselor Extraordinaire.... SFC (Join to see). He is a wealth of knowledge. He also knows a little bit about Career Counseling.

I will say, however, that in my personal opinion, Career Counselor should NEVER be a "used car salesman." Career Counselors should be what the name implies... a COUNSELOR. Sometimes you have to tell a Soldier what they need to hear rather than what they want to hear. Sometimes, even if you REALLY need another person to re-enlist to make your numbers, it is a bad idea for that Soldier at that point in their life. Don't sell that Soldier the Army. Please, please, PLEASE, please don't do it.

If you are looking at switching your MOS to career counselor because you've been told you're basically a good bullshit artist, you definitely don't need to be in my field! Go out and enjoy recruiting duty for a few years, grow as an actual NCO, then rethink your future plans when your tour is about over.