Working at Apple, I don't know one customer who wants to go back to Tiger. Keep in mind, people don't go online to post compliments, they typically make complaints. That fact alone isn't representative of the overall reaction to any particular product (in this case Leopard). Most of the customers (actually, in my case all of my customers) LOVE Leopard over Tiger, especially the PPC users who have noticed a double in speed increase.
Leopard installed fine on my Mac Pro. No complaints here. Vista on my slave drive, well, that's another story.
You have to admit those ads are really stupid. No wonder they've been forbidden in a certain number of european countries.
The first thing that always puzzled me, is that they've put a young nerd to play a Mac and an old fart to play the PC. In reality, when you go shopping, that's the exact opposite.
Watching those ads makes me wanna stick to PC.