I prefer Lion to Snow Leopard.
I find myself appreciating the more controversial changes, like reversed scrolling and hidden scrollers. I followed Gruber's advice and suppressed the impulse to switch the defaults back to Snowpard behaviors and find that I'm less happy when I have to use Snowpard now.
Meanwhile:
* Mail.app under Lion is the best mail UX they've ever shipped. It's not a small improvement over Snowpard; it has a more reasonable layout now that makes Smart Folders make more sense, and search seems to have been completely rebuilt and actually works now.
* I find myself liking Mission Control enough not to mind not having vertical virtual desktop arrangements.
* Preview can sign documents now!
* The Filevault fix is huge for me (Filevault is now a bona fide block level FDE), since it means I don't have to use PGP WDE, which was a debacle.
My sense of it is, there is zero opportunity for someone to compete with Apple and Microsoft on conventional desktop operating systems, and the problems O'Reilly has with OS X are not generally going to be shared by people like my dad, who are (a) the only people Apple really cares about because (b) they're where all the money is.