You're getting it anyway, but you're wondering if people like it?
Personal background: Longtime fan of Warcraft, Starcraft, AoE, MOO2, etc. First played Civ1 on NES a couple years ago. Bought Civ3 and enjoyed it for a year. Bought Civ4 a month ago, and am playing on a slightly below min specs computer.
Why I like cIV better than Civ3 ...
Less tedium: Cities. You aren't in the middle of building your third city when your first city is in a contant state of civil disorder. Unhappy citizens just stop working rather than riot, so you don't need to check in on a city after every point of growth to make sure the happy/unhappy balance hasn't been thrown off.
Less tedium: Workers. No pollution. Thank god. And more choices. When setting up cities you aren't just thinking about what to mine and what to farm, you're thinking farms, mines, windmills, watermills, woodshops, workshops, cottages, camps, plantations ... I think I got 'em all. You can really think about what to do with workers.
No corruption. You're no longer stuck in that position where you colonize that island or continent across the ocean and then have to deal with a city that takes 80 turns just to build a harbor. Corruption is replaced (quite nicely) by nation maintenance. Yeah, it can be a pain. I've had a couple games where I thought I was doing so well by settling half my shared continent in the time the AIs still had 3 cities, only to realize that I was at 20% science and only pulling in 1gpt. But it's a reminder to pay attention to things other than "where's the next settler factory?"
Better war. It's quite simply more fun than building a dozen of the same unit (and maybe half a dozen artillery) then sending them in one stack. And combat upgrades are pretty sweet too.
Open Borders. I always hated ROPs. There'd be no reason for me to build half my empire on the other side of an AI, so why sign a ROP? With OBs, you have reasons to accept them: trade routes, missionaries, nicely improved relations.
Religion. True, it's not perfect, and it's not the game changing thing that some would have you believe, but it's pretty cool. It can affect diplomatic relations, gives you "spying" abilities, and can get some big money into your coffers (found a religion that takes over half the world, then build the shrine).
Pretty graphics. They slow my game down, but they're nice to look at.
Right-click "go to". This was hard for me to get used to, but now I think it's the single greatest improvement.
Diplomatic relations. The ability to take a look at one screen to see how others feel about you and why, and also see how they feel about the others if pretty nice. Keeps you from doing something silly like declaring war against your best trading partner's best friend.
Cultural borders make sense.
More techs.
Better balanced wonders. I always thought something like Art of War was way overpowered. Though now that they're mostly weaker, I'm less likely to build them.
Barbarians who are a real threat. More fun, and more of a pain. You can no longer rely on two spears in your border cities to beat back the "horde" of six barbarian horsemen. You've gotta deal with axemen and swords.
Specialists. Maybe it's because I never understood Civ3 specialists that I think cIV specialists are so cool, but they actually DO something noticable.
What I don't like about cIV ...
I miss the instant feedback from my foreign advisor ("they might not take this deal ..."), but it makes dimplomacy a bit more of a thinking game.
The warning sound made when an enemy destroys your improvements is very, very annoying.
No ability to instantly go to "an enemy spotted ...", though you can use the event log to go through things like that.
No more prebuild. It makes more sense, but I miss it.
In the end ...
You'll probably enjoy it. You'll have issues with some parts of the game and you'll want a patch or mod to fix somethings you don't like. You might have tech issues. But in the end, an entire weekend devoted to playing WILL happen.