I was looking forward to this game for two reasons: 1) I loved Simcity 2000 and it is one my favorite games, and 2) I was disappointed in Simcity 3000, a game that did not satisfy my need for a NEW Simcity. Simcity 4 succeeds where Simcity 3000 failed: it adds many new features to the Simcity gameplay and makes the city-building experience fresh again.
The most obvious change in Simcity 4 are the regions. You can build many cities that are actualy connected to each other and so every city's neighbour is now "real", unlike in the previous Simcity. Regions are an essential aspect of Simcity 4 and it is no longer possible to have a single successful city. You'll HAVE to build MANY cities now. But being able to designate each area as a commercial corridor or another as a farming community or another as a suburb is very cool. What isn't cool is the new, useless MySim option, which allows you to have your characters from the Sims live in your city. They are supposed to give you feedback about your city, but they aren't very helpful.
Also, when you zone an area, the area you zone will now be divided into "lots". The addition of lots gives you more control over your city, but it can also make things more fustrating since lots must be connected to a roadways. As for roadways, there are two types that you can now build: roads and streets. Roads are high capacity roadways while streets are low capactiy but are cheaper. Things can be fustrating when your citizens insist on using streets instead of the roads.
All these changes, among others make Simcity more realistic. But they all add to the amount of micromanagement that you'll have to do. Things can become fustrating when you don't know what you are doing. And the useless manual (can you say "brochure"?) doesn't tell you how to play the game either. For that, you'll have to spend an additional $20 for the official strategy guide. Personally, I like lots of micromanagement in my game so I enjoy Simcity 4.
Simcity 4 is still fun, and it is a different experience from other Simcity games, so you won't feel like you're playing the same game as before as with Simcity 3000. This game is just not as accessible, and therefore potentially not as fun, as Simcity 2000. But any Simcity veteran should still check it out. Just be prepared to spend more money for the strategy guide, because you'll need it.