imac .. its WAY better. you'll be happy about it once you have it ,trust me! and also better graphics..

actually mac can do more then Windows which comes with sony vaio ,because iMac can run windows
with bootcamp ,so its like basically having two computers on one machine

iMac offers a truly complete computing experience that is difficult to duplicate on any other system. The J-series has that blue-ray drive built in and the newer processor.

From my point of view, it comes down to whether you want to have the relatively blissful OSX experience or the improving Windows 7 one.