I had forgotten how truly enjoyable the Sims was until going back to this game. Compared to the Sims 3, this game's response is instantaneous. As soon as I want it to zoom, it zooms; when I want to save, it does so quickly and efficiently, and it doesn't bog down the rest of my computer, either. This is one of the most optimized games I've played in comparison to the Sims 3, which wasn't made by the same company that made the first two; surprise! (Deja vu via RollerCoaster Tycoon's situation?) I like the graphics a lot better in this game than in TS3 as well; the sims look and feel more expressive and their interactions are far more exaggerated and interesting. Maxis's humor seeps through this game thoroughly.
The Sims 2 also happens to be one of the most heavily modded games I've ever seen. Countless sites are dedicated to messing with meshes and objects that you can use in your game to modify your characters and houses, a feature that was largely ripped away in the Sims 3 (it's still possible to edit TS3 quite a lot, but the abilities given to the modders are nowhere near as advanced as TS2's).
If there was only one feature I could take from TS3 and put in TS2, it'd be the ability to walk around the neighborhood as if it's one seamless unit. As such, I will be playing both TS2 and 3, with a heavy preference for the former but a subtle appreciation for the latter.