Here is a video which compares the differences between the Apple TV and the Google TV and recommends the better of the two.
What I Think?
Indeed, I have to admit that comparing the two TVs is just like making a comparison between apples and oranges, because they are just too different. Despite so, I have to agree with the dude on Youtube and say that it really depends on what you want to do with your TV.
You would choose the Apple TV for sure if you want to get access to a variety of movies and TV Dramas, Youtube and Netflix for downloading as well as having music and videos stored in iTunes on your computer.
However, should you not want to rely on iTunes and want full web browsing capability through your TV set, Google TV would be the one you should be gunning for; it also allows access to thousands of movies, Netflix included.
But just in case if you want the best of both worlds, I would recommend that you get a new HD TV with built in Google TV, then an Apple TV device through one of the extra inputs on the back of the TV, and you will have the full panoply of home media services – music, movies and web browsing.