The Märzen style of beer that gets served at Munich's Oktoberfest festival is a malty lager with some caramel character and a straightforward clean-tasting appeal. It's a great training-wheels beer style to introduce to friends who think they don't like craft beer, and it's widely available throughout the football season.
The Samuel Adams version differs from the Märzen style with a bit more hop flavor than its more traditional German cousins, but not so much as to muddle up the impression of a malt-forward lager. It's a good example of the style, but the real reason we reach for it so often at this time of year is that it's so much more likely to be fresh than the Munich versions (such as Hofbräu and Spaten), which are fantastic, but have to contend with the double whammy of potential cardboard flavors developing with age as they cross the ocean, not to mention skunking from light that seeps through the green bottles. Samuel Adams Octoberfest is less likely to be skunked in its brown bottle, and if you opt for cans instead of bottles, you know for sure there's no way that the beer inside will be light-struck.