Auto-complete can be both annoying and useful, but it is also quite configurable. It's worth playing with the options.
I turn off the more aggressive completion options. That way it only provides a list of members when I need it and doesn't interrupt me while I am typing names and keywords.
I found out, after turning it off, that I did use it all the time in 2010! However, and this is key, in 2010, it was SMART! If I typed out a variable name who's type was a class, and then typed '.' or '->', I would get a list of members. Very useful! Now, with 2012, it is frantically trying to guess what I am going to type at every moment. Very intrusive!
And it is another featured gimped in 2012. I can turn it on and I can turn it off. What I cannot do is configure it.