So look, heres the bottom line: Macs arent BAD per se. But Ubuntu, especially since the release of Feisty Fawn, is really just as good an option for the vast majority of the population.
The opinion is http://openswitch.org/journal/why-i-like-my-ubuntu-box-more-than-my-imac here
At first the iMac was a cool product, all shiny, all aluminum. The construction was the selling point; I also liked OSX Tiger. I went all-in too. I bought Photoshop CS3 and a dozen other paid applications like Transmit, Textmate, etc. Everything went well for a while. I tried Quicksilver and found it marginally useful at best (experts disagree).