No real problems. I'm very happy with my PS4, being a very multi-functional device. It's now my primary blu-ray player. The only small issue is the fact that US PS4 accounts have access to the Gametime NBA app, which isn't available in the UK. Wouldn't mind having that app, but otherwise i'm happy.
And with the rumours of The Last of Us coming to the PS4, wow. If true, will give me the chance to play this game for the first time and see what it's all about.