Microsoft Community Contributor
I noticed that, too. Knew it was more than Windows Defender with a facelift.I have been running MSE since I first installed Win 7 (RC version). I also believe it uses very few system resources. I have never been successfully attacked with MSE in place, but I also am proactive with my security. I always update apps and signatures (MSE updates sigs each day), and use a multi-layered approach with both a H/W and S/W firewall in place. I also use Sandboxie when I will be surfing to sites I am unfamiliar with, although the newer browsers are now including sandboxes by default. (Chrome does and I believe IE 10 will have it)
I am very pleased with MSE, and like you said FREE rolls off the tongue so nicely. MSE is very highly rated in comparison testing.
Note: It appears MS resurrected Windows Defender in Win 8, but actually uses MSE and just renamed it Windows Defender. It is installed by default on Win 8.