What a question.
I could ramble on for hours but I'll try to keep this brief.
Basically, I think it's definitely worth getting if you like the city theme. Here's my list of pros and cons...
Pros:
-impressive city atmosphere, especially at night when the skyline looks gorgeous
-lots of new options for socializing
-lots of really funny surprises
-great-looking modern furniture, new items in almost every category
-a lot more stuff to do when going out at night
Cons:
-building within the city is quite limited
-getting around the city can be a bit annoying
-some of the old bugs are still there and there are a few new (mostly minor) glitches
-can be a bit dreary-looking in the daytime
Overall, I find it has a higher "fun" factor than the other two expansions.
If you're not sure, I'd say wait a while before getting it. Most likely there will be a patch to fix some of the more obvious glitches, so you could save yourself a little frustration by waiting for that.