I haven't played Societies, but I have played Sim City 4. It's a solid entry to the series, with more depth and many new features and bits of realism that weren't in 3000. However, I've encountered technical issues with it on a number of PCs, and I've heard from others that it is indeed somewhat shaky. Your specs need to be WAY above the recommended mark to run it at an even framerate, even on low graphics settings. Beside that, though, it's a quality game in my opinion.
