I have not played Cities:Skylines, but have kept up on it because I was very interested there for a time. I heard the main complaint was that the game was ALL about traffic. But that since the initial release, there have been mods released that can turn the difficulty of traffic management up or down to your taste.
Also, that it's not as much a game as it is a sandbox. With SimCity (the older versions), there were always money goals, population goals, etc... but that with Cities, there is not much of a "challenge".
Now, with it having been out for nearly a year at this point, I imagine there are tons of mods for it that can fine tune it to your taste. By the time I get around to pick it up, I imagine they'll be ready with the sequel.