I just did a side by side comparison of my Oktoberfest (chronicled here: http://homebrewtalk.com/showthread.php?t=23772 and here: http://homebrewtalk.com/showthread.php?t=32764) with a Paulaner Oktoberfest/Marzen. I absolutely hit the mark!!! I couldn't tell much difference between my homebrew and the commercial version. The color and clarity were perfect. The taste was right on - a nicely balanced malty brew. This beer is the clearest best beer I've ever made. I love it. FWIW, it was the extract version of the Ayinger Marzen from Clone Brews.
A year ago, I got into this hobby because I thought it might be fun to brew my own beer. I never believed that it would be possible to brew something comparable to a commercial beer. When I thought of homebrew I thought of "swill", but since I'd gotten a nice big bonus I bought a starter kit because I thought it would be fun to try it despite my beliefs. My first beer wasn't much better than "swill". I fermented a "Helles" recipe that my LHBS owner designed for me with a dry lager yeast at about 70 degrees. Man, did it have lots of fusel alchols. It was nasty. Not one to give up, I went back to the LHBS and bought more ingredients and fermented in the bathtub full of cold water. While that was much better, it still left a lot to be desired.
By reading as much as I could get my hands on and following the great advice I've found on Homebrewtalk.com, I've learned that it is possible to brew beer BETTER than the commercial breweries. I've got a Helles that I brewed from a recipe someone here gave me that is pretty good. I've brewed a couple of German style pilsners that are decent enough, and now I've got a great Oktoberfest that will carry me for at least the next month.
I've moved onto AG, and even designing my own recipes. The first two AG I did were Weizens and while I didn't really care for them it's not 'cause they weren't good beers - I found out I just don't care for the style. Friends that like wheat beers have raved about them and my comparison with the commercial variety was decent enough.
Thanks guys for all the great site and wonderful advice. I expect that I will be brewing GREAT beer that I really like for a long time to come.