My Lion experience was a big bag of hurt. I say 'was,' because I'm back with Snow Leopard now.
My first Lion upgrade was done the Apple way, built on top of Snow Leopard. My aluminum iMac bogged down with delayed Finder responses, tons of spinning beachballs, and broken Wifi.
My second Lion upgrade was a clean install. The clean install got rid of the laggy Finder conditions and spinning beachballs, but the Wifi was still broken.
For some reason, Lion's Wifi constantly keeps "Looking For Networks," and simply loses connection about once every half-hour of regular browser use. I consistently got Wifi back by restarting Wifi or running Network Diagnostics, but the process was a pain.
Under Snow Leopard, Airport does not constantly search for new Networks, and my internet connection is rock solid and quick. Under Lion, my Wifi is simply broken. Even when connected via Ethernet, I was getting weird connection issues and slowdowns.
So yes, Lion is a big bag of hurt.
All these posts on this thread (and elsewhere) that say nothing more than: "I don't have these problems, so there's no problem," are inane and do nothing to clear up the mess that is Lion.
The point isn't that YOU, or YOU, don't have problems. The point is that a certain percentage of people are experiencing these problems. If 10% of Lion users are seeing Lion as a big bag of hurt (a completely arbitrary number, by the way), then Lion has a problem.
There is no excuse for Apple producing a broken OS. I shouldn't have to learn how to create a bootable disc of Lion and to do a clean install, and all that to have solved only part of the problem. The Lion that Apple charged me $29 for is broken.
At this point, after having used Windows 7 on the PCs of friends and family, I see absolutely no reason to pay the Apple premium for my next computer. The Apple advantage (It Just Works... Pay Extra For Quality... etc.) doesn't justify the expense any more.
I've been an Apple user since the Mac Plus, and who knows, I still may stay an Apple user for certain products. But after my experience with OSX Lion, my loyalty to Apple has vanished.
The part that sucks is that Apple will deny, deny, deny, and then when they come out with a fix, they'll call it a new feature.