Oktoberfest beers are lagers, which means they are fermented at colder temperatures. They are technically harder to make than ales, and they have a different flavor profile. A little more subtle than ales, but still tasty. They tend to be a very clean, refreshing taste. If you've ever tried Red Stripe, that's a lager.
I actually tasted 4 or 5 Oktoberfest beers for this tasting, but lost track of which beer was which after the first few. So I've only got two full sets of tasting notes. Sorry. Oktoberfest is a strong beer, at around 5-6% alcohol, but it doesn't drink like one. After those two reviews, I will give my impressions, overall, of the other beers.
1. Weihenstephaner Oktoberfest Marzen
Nice head. Not too foamy, but it didn't disappear right after I poured it, either. The was a lovely amber color. I didn't get much smell from the glass, but once I tasted it, I could detect a good malt flavor. It wasn't very hoppy. The hops I did detect were at the front of the sip, the malt rounded out the back and provided a nice aftertaste. As I drank the beer, the hops built up a bit on my tongue and became more noticeable, but still a well-balanced beer. This was an easy drinking beer, and didn't feel like the 5.6% alcohol that it was.
2. Leinenkugel's Oktoberfest
Redder than the first beer. Not much head at all, and what head there was faded quickly. A roasted, toasted note at the front of the sip. A tad sour. Very little hops, but hops were at the end of the sip. Somewhat bitter finish. There was also a malty flavor I tend to associate with pilsner beers at the end, as an aftertaste. The only way I can describe this is like a Bud or a Labatt's finish.
I found it interesting that, though the flavor profiles were pretty much the same on these two beers, each beer expressed those flavors in a different way. Everything I was tasting was pretty subtle, and after a while, the beers began to blend together.
But all the other beers I tried were very similar. Perhaps more hops for one, different malt taste on the other, but all were medium- bodied or lighter, fairly carbonated, and easy to drink. I tended to prefer the German Oktoberfests, but this may have been bias on my part. Would be interesting to do a blind tasting at some point to see if this holds up.
In short, you can't go wrong with Oktoberfest, especially if you like lager beer. I'd suggest getting a few and trying them to see which you prefer, at least one German if you can.
And, as I've said before, if you can find an Oktoberfest on draft, done by a microbrewer, drink that. You will quickly learn what "fresh" beer really is.
Don't drink and drive kids, and have fun!