Yes, as a stand alone AV it is very good ( there are many tech sites that compare all the popular AV's to each other, try a google search).
The big plus for me is the low background footprint and the fact it is designed by MS to work with MS. Other paid AV's make your PC soooooooooooooooooooooooo slow!!
I also use Malwarebytes, works well with MSE and also run Spybot SD (without the "teatimer") every few weeks.
In my experience, NO av programm will find every piece of malware and so on, thats why I use secondary non-intusive scanners aswell. All of the above are FREE and can highly recomend them.
Cheesrs
PS An interesting article for the MAC fan boys who think that it is more secure
Mac OS X security myth exposed - Techworld.com