Usually channels are the same as in the US version, but most of them won't work outside the US.
The basic iTunes channels (Movies, TV, Music) will work differently depending on your itunes account. Each country has its own itunes account and the corresponding movie/tv/music titles and pricing.
I have a US itunes account and my Apple TV works just fine outside the US (for general channels). My other channels work only if I am using a DNS or VPN.
Some channels, like Disney, ABC and others only work if you have US cable subscription. Skynews and ABC News work w/o subscriptions.
If you pay for Netflix (and netflix is available in your country), it should also work fine.