The difference is astonishing. Here’s the picture I uploaded yesterday with the game running in Parallels:
And here’s the same picture running in Boot Camp (I copied over the save file so everything, including the time of day, is exactly the same):
In my opinion if you really want to play The Sims 4, and you’re on a Mac, then Boot Camp provides a much better experience. As for the game itself, I’ll be back with my personal opinion on it over the next couple of days. Suffice to say I’m still working on Huckleberry Bay in TS3 and am still building and playing TS3.
These pictures were taken in game in Boot Camp. I’m running Windows 7. My Mac is a 15″ MacBook Pro, 2.6Ghz Intel Core i7, 16Gb RAM, NVIDIA GeForce 650M 1Gb.