Well, it took 35 hours and a city of nearly 60k pop, but finally starting to see a few oddities in Cities: Skylines. So far it's very minor and can be mostly ignored. At some areas in the city (seems like the same small section of road each time), a car will just randomly stop for just a second and then continue on. Not all the cars, but maybe 1 car every 30 seconds. It doesn't slow things down too much. But it's clear that the game is having a bit of difficulties processing where each car is trying to do/etc. For just that small section too, it's not widespread. Like I'll see it in like 5 spots tops in the city currently, and my city is like 6 areas spread out or so now. so it's very very small, but def something you notice. Performance wise, still holds up well. Maybe not as 100% smooth as the early days, but still like 90% good.
Still, with 35 hours put in, and I haven't even put in all the things (like only just put in a harbor and haven't unlocked an airport yet). I'm having a lot of fun with this game. So if you are in a Cim Sity like mood, I still very much recommend it! Esp if you might play more on the go.