Recently switched to join.me and I'm loving it. Easier for the inept person you're helping to get started.

Also, if you're using it for remote presentations, all you do is email a link and they can see your screen directly in the browser.

I use Teamviewer all the time and find it very useful. I need to spend a little time to look at how the connections are made though—I'm not confident that it's secure since you have to enter an ID and password that are (I'm assuming) authenticated by a different machine controlled by Teamviewer. I wonder if the connection is sent through their computers (to get around router issues) and therefore susceptible to capturing passwords, etc. or if the connection is handed off to the two machines after the ID / password is handled.