I just got Sid Meier's Civilization V a few days ago. I haven't had a whole lot of time to play through it--just ran through the tutorials and maybe halfway through one chieftan-level game. Keep in mind this is more or less a first-impressions review, since I haven't explored all of the functions of the game.
A few things I like:
1. The new City-State system is pretty awesome. Basically, these are NPC civilizations you can interact with. You can conquer them like normal cities, or you may forge diplomatic relations with them. Mostly this involves bribes, but can also involve defending them against other players, completing missions, and supplying them with units. It's simple but a very nice (and somewhat realistic) concept. (Since you get all sorts of bonuses for being diplomatic, it is usually best to ally with them instead--though not always.) The best part is that the city-states are the ones that will determine a diplomatic victory--which actually makes that type of victory useful for once.
2. The interface is very clean. I especially like the fact that you can more or less look around--although you can't really do anything--while the other players are taking their turns.
3.Technology pacts are awesome. You can't trade technologies anymore, which at first seemed odd. But the new pact--where, basically, two civilizations spend some cash, wait 20 turns, then both get a free new technology at random. I'm sure the randomness part might screw a player every once in a while, but all in all it seems like a nice addition, where it adds diplomacy and risk into the mix.
One thing I like but probably shouldn't:
1. The graphics are not mind-blowingly awesome. But they're certainly on par with what else is out there, which is fine, and is very functional. I don't want to have to buy a new graphics card every four months, and this is Civilization, not Starcraft 2. I am very happy with it, but I can see why others wouldn't.
A few things I don't like but probably should:
1. I'm not sure what to think about the Social Policy concept. I like it in the face of it, but one of the things I liked about the previous Civ 4 civics model was that you had to make a choice in what your society looked like--you had to give up X to gain Y. With the new model, you still have to make some choices, but not nearly as many as before. You can more or less have it all--I think there are only two out of ten that are mutually exclusive.
2. The Wonders are much less powerful. I understand why they did this, since Wonder Addiction can wreck a game, but I still loves me some wonders.
3. Production seems mind-numbingly slooooow. I'm sure this is good, since the previous strategy for Civ has usually been "build everything in every city," and now you pretty much can't. Or perhaps I'm just not doing production right, I don't know.
A few things I don't like:
1. The technologies seem out of whack. Technologies and improvements don't really match up--why would Economics allow you to build a Windmill? Printing Press allows the Theater? The Courthouse is made possible by...Mathematics? I'm sure from a gameplay balance it makes more sense, but it irritates me. (To be fair, Civ 3 had the same issue, which was partially fixed in one of the expansions.)
2. I am not certain, but so far the AI seems overly aggressive and slightly irrational. This has always been the case in Civ games, so it's not a big surprise. But I haven't had to deal a lot with it yet, so I'm not sure.
3. Automating workers and scouts will cause them to blatantly violate trespassing agreements with City-States. This seems like an oversight that I assume will be patched, but we'll see.
Now, I haven't dealt extensively with combat--mostly just against barbarians--so I can't speak much to it. I expect that wars will be shorter are more tactical in nature, but I don't know. And I don't know if winning the game is balanced or not, because I haven't finished a game yet. Still, so far, I recommend it.