I decided to buy Civilization V about a day after launch. I don't know why the wait. It's certainly part of the reason why I've taken the last few days off (that, and a pretty serious creative drought), so for your trouble you will at least get a preliminary review.
I never got into the Civ series as such; my entry point to Sid Meier-brand games was Alpha Centauri. I was too much into Age of Empires to bother with the slower pace of Civ 2, I gave Civ 3 a pass for whatever reason, and I've tried out a few games of Civ 4. So what do I think of Civilization V? Compared to Civ 4 it's a few steps forward, a few steps back, and a few steps sideways. While it carries on the visual aesthetic of Civ 4 for the most part, the feel of the game has changed appreciably in some ways. Compared to Alpha Centauri, I think Civ 5 is good. Better? Maybe not, although that could be my preference for Science Fiction.
What I like about Civ V is that Firaxis has pared down the interface a little, and made it a little more helpful. Important events/cities/units get highlighted, the pop-up notifications are placed where they're noticeable but not too obtrusive, and most of the menus are tucked away by default so that you can see more of the map. It's good. I think it's going to be non-threatening to a new player of the series. Speaking of paring down, there are now only four advisors (Economy, Foreign Affairs, Military, Science). I think the number was getting out of hand in Civ 4. Military units don't stack anymore, which is - hear me out now - a good thing. For one it makes battles a lot more readable. It's a lot easier to gauge the threat level when you don't have to peer into every stack of units to see which has 5 guys and which has 15. As every review will also tell you, it means that mountain passes are actually of strategic value for city placement, because you can bottleneck armies in tight corridors (Thermopylae can actually happen in Civ V, where it probably couldn't in the previous games). Culture points now work to expand your city borders, you can buy new tiles for your cities to work (awesome when you really need to get access to a specific resource). You can also use Culture to unlock policies, which have replaced the civics of Civ 4 and AC. I do and I don't like this change. I remember thinking that it would be pretty cool if you could have a "build your own constitution" mechanic, where you could adopt certain laws and principles...and this is pretty much that. I'll get to what I don't like in a second. Finally, it's pretty awesome that the other leaders talk to you now...IN THEIR OWN LANGUAGES. So you meet Catherine the great and she speaks friggin' Russian at you. + Immersion!
There are a few changes that I'm ambivalent about. The switch to hexes doesn't feel like it makes a huge difference. The unit promotion mechanic is neat, but the initial options are rather small bonuses, or a full auto-heal to full health. So I either set my unit on the path to improvement (in which case it is still at low health and probably dies), or I heal it...and it doesn't actually get any better. The addition of city states is...well, I dunno. They give out quests that I'm never conveniently located to accomplish, and they get angry when my units are set to auto-explore and run through their territory. And as far as I can tell they're a resource sink where you blow cash on influence that degrades. Essentially, city-states are needy gold-diggers, and I'm not sure I like them.
And finally, the stuff I don't like. Religion's gone (except for the "piety" civic, but it's not the same thing). Civilization 4's treatment of religion was utterly respectful, and it really did add a historical element which had been missing from the game. I guess I understand that it's gone in the name of simplicity...and it's weird that I would whine about removing religion from a game, but here I am. I also sort of miss the old-school civics from Civ 4 (and also Alpha Centauri), if only because they were a little more concrete than the new policies are about how your government/economy/society functioned, and I'm kind of a stickler for detail that way. Oh, yeah, and the game needs a "formation" command so that you can arrange your armies to move in blocks for convenience. That would be pretty neat. Oh yeah, and I don't like the happiness/sadness mechanic being a civ-wide thing rather than base-specific. Also, the game says unhelpful things like "X unhappiness from population" without telling you which direction you want to shoot for. Are there too many people? Not enough? HELP!
Oh, and the intro cinematic is really pretty but did you have to make it play EVERY TIME I START THE GAME? Yeah I totally renamed the file to "____.old" so now it just has a mild seizure and tosses me into the menu. Pro, I know.