I've played Settlers a handful of times, and routinely enjoy it, although I can see that I'm not "OODS"ing fast enough (thanks to a recent HOT geeklist http://www.boardgamegeek.com/geeklist/22622 - more on that later). This was my first play of the Cities and Knights expansion, and its first appearance at my regular game night group.
Setup was straightforward. (Hurray for the tile frame included with C&K!) I placed my initial settlement near some plentiful resources, and not too far from a harbor, and my initial city at one of only two vertices where all three commodity producing tiles met. I speculated that lacking these cards would prove dangerous, so I took that trade-off against the loss of doubled resources. This also left me without easy access to brick, though, which may have been short-sighted.
The initial couple of turns were standard fare, with perhaps predictable oohs and aahs over the first knights being built. I actually let "I forgot you could do that" escape my lips. I get the Deserter progress card, and promptly use it to make my first major miscalculation of the game. I swiped a knight from the only player in the game with two of them, leaving each of the four of us with one. Unfortunately, there were 5 cities on the board, and the barbarians laid waste to the countryside. If I'd picked one of the others to swipe from, I could have saved us from all losing a city and just thrown the one guy on the mercy of the rampaging hordes.
We all began rebuilding our cities (and a plentiful supply of knights - our first barbarian attack turned out to be our last). My choice of location for my city began to pay off (good commodity generation). I got the longest road, but lost it. In a flurry of activity, I bought two more road segments and built another two free with a card. Longest road again! But not for long, as my road was cut by a marauding knight. Not having a Fortress yet, I couldn't upgrade my knights enough to displace him - drat it! Things went from bad to worse as I found myself zapped by the robber, and suddenly bankrupt of resources. We look at the clock - 5 hours and more gone by; players started openly looking for ways to give the leader what he needed to get his 13 points and end this thing.
Suddenly I got the big idea for my last big miscalculation! A quick count on the board tells me there's a few more cities than knights. My only city is a Metropolis, so I figured I'll wave some sacks of loot and big turkey legs at the barbarians; I moved both my Active knights needlessly in order to deactivate them and ensure we'd be plundered by Vikings. Alas, I missed the rule that said upgraded knights count as more than one. There was more than plenty of knights to fend off the looters. The barbarians shuffled away, muttering something about "teasing". The leader builds a settlement and connects his road, and it's done.
Barbarians really encourage two things: knight creation (obviously) and aggressive settlement creation (more subtly) because settlements are immune to attack. The net effect is to push players to spreading out more widely than commonly occurs in Settlers.
So much happens so routinely in this game, that it's difficult to keep track of what you are trying to do (again, see the geeklist bit about the OODS loop). Too often in this game, a trade opportunity came up where I was asked what I needed. I was embarrassed to realize I didn't know what needed. I didn't know what my plan was for winning!
Indecisiveness costs ages of time in this game. I watched a few trades of cards that took far longer than they should. Know what you want to do and do it, or hand over the dice. This was our first outing for this, but 6 hours is too long for this game.
C&K offers some great new strategic considerations and a great deal of fun. Our group is planning to revisit it soon.