And they won't make for happy reading at Microsoft's campus in Redmond.
The cat's miaow
"In my view, Leopard is better and faster than Vista, with a set of new features that make Macs even easier to use," says Walt Mossberg of the Wall Street Journal and All Things D:
"Every piece of software and hardware I tried on two Leopard-equipped Macs... worked fine, exhibiting none of the compatibility problems that continue to plague Vista.
"My old Hewlett-Packard inkjet printer, for which Vista lacks the proper software, worked instantly in Leopard, even over the network.
"And, unlike with Vista, it was able to print on both sides of the page. I popped my old Verizon cellphone modem card into the test Leopard laptop and it worked, too, with no software installation or tweaking."
Leopard leaps forwards?
Mossberg heaps praise on new Leopard features like Time Machine, which offers 1-click automated backup of all your music, movies, photos and files. However he also argues that Leopard is an evolutionary rather than a revolutionary leap forward:
"Leopard isn't a must-have for current Mac owners, but it adds a lot of value. For new Mac buyers, it makes switching even more attractive."
David Pogue of the New York Times is more forthright about what he doesn't like about Leopard:
"The most serious misstep in Leopard is its new see-through menus. When the menu commands — Save As, Page Preview, whatever — are superimposed on the text of whatever document is behind them, they're much harder to read.
"Often, Apple's snazzy graphics are justifiable because they make the Mac more fun to use. In this case, though, nothing is gained, and much is lost."
However he also thinks that Leopard could tempt 'Windows refugees':
"Mac OS X requires no serial number and no "activation"; it's not copy-protected. It doesn't clutter the desktop with crippled bits of free-trial software from other companies. There are no nagging balloons or come-ons."
This cat has claws
"Leopard is powerful, polished and carefully conceived. Happy surprises, and very few disappointments, lie around every corner. This Leopard has more than 300 new spots — and most of them are bright ones."
In his review, Edward Baig of USA Today does throw Microsoft some small crumbs of comfort:
"Long before Leopard pounced onto the scene, I rated OS X superior to Windows for most consumers. With Leopard, Apple's operating system widens its lead aesthetically and technologically.
"Whether the sixth major release of OS X in as many years puts a dent in Microsoft's dominant market share is another matter entirely."
Apple critics won't hesitate to point out that Mossberg, Pogue and Baig are all renowned Mac fans - which is arguably why Apple gifted them with copies of Leopard a week before everybody else.
You'll be able to read our First Look at Leopard tomorrow, when our boxed retail copy arrives.
We're also meeting Apple for a Leopard briefing on Monday, so please contact us if there are any questions you'd like us to ask on your behalf.