Aptitude vs. apt-get

[Steven Vollom]

What are the differences between the two?  I typed in sudo apt-get install 
updates and did not get the response I expected.  Then I typed in sudo 
aptitude and got what I expected.  I thought they were pretty much the same.  
Was I wrong?  Additionally, while I am learning this process, I try to use 
kdesudo most of the time, but when installing new applications I usually use 
sudo apt-get.  I realize that kdesudo is for GUI aps, so that part is not 
confusing.  Yet sudo apt-get usually works for GUI's as well, I believe.  I 
have used aptitude the least, but have it installed, and in the case of 
updates and safe-upgrades it seem to work the best.  Don't bother if this is 
too stupid a question, I would just like to make a permanent memory of the 
differences.  I suspect I will learn this in time anyway.  Thanks!

Steven