Just shut it off after 9+ hours straight. I'll post more thoughts later but here's some quickies for now:
* I like the focus on less cities and more techs with many ways to play and customize, all the way down to the units.
* They REALLY changed how some of the city improvements and Wonders work.

I raced to get the Great Lighthouse so my ships could take to the oceans and explore the world. Well, I should have read what it actually gives you first. I sat there bug-eyed for at least a minute. It was a good time to take a nacho break.
* I'm about an hour or so in and I have 2 cities pumping along, I'm scouting the rest of the continent for placement of a third. At this point I have a few workers scurrying around building the Might Russian Transcontinental Stone & Mud Road. I zoom back to my capital and I get this message: "A forest has grown near Moscow," folloed by a clump of trees engulfing an area that I was planning on developing next! I was stunned and impressed all at once. Very cool.
* Religion is wacky. I like the way it is used. I had a real challenge trying to isolate my civ from other civ's religion with absolutely no luck.
* And has anyone else been crushed by another civ completing a Wonder mere turns before you do? I got 300 gold, sure - but I lost hundreds of years of improvements.
*
NO. MORE. LOST. AT. SEA.
All said, I love this game. Much better than Civ III which was cool at times but was more frustrating than Civ II. I think they got it right this time. It can be as simple or as complex as I want it to be so far. I'm honestly surprised it's *this* good. To me - Civ is back.
Graphically the game chugs at times which drives me nuts. I need to either get a new computer or finally get around to fixing my custom rig that had a HD crash earlier this year. Never thought I'd be saying that about a Civ game.