I have both OS X 10.x and Ubuntu 7.x running on separate laptops, and have used them for over 2 years now. The similarities are outstanding in more than a few ways. Below is PART 2 of my reviews and summary of main features of the latest Ubuntu 7.10 (codename Gutsy Gibbon) which have made it so appealing over Apple's OS X.
First and foremost, lets not forget that you get what you pay for, and since Ubuntu is free compared to the OS X Leopard, there are going to be some obvious added applications and tools in OS X which Ubuntu does not have (similar applications can be added in Ubuntu in most cases, again at no cost since there are no license fees and its open source).
My intent here is to educate the average user on their options.