When I first got my iMac I confess to having been quite disappointed. For one thing, MacOS X Jaguar was kind of crummy in my opinion. Mac users tend to be a fanatical lot and as a result tend to live in denial about the short comings of the Mac. It's like they have this unspoken rule not to publicly speak about all the problems Mac users deal with.
Not being part of that cult, I had the audacity to point out the short comings here on JoeUser (will put together a list of links shortly to those blogs). The response was predictable - massive flammage and denials.
I have two basic problems with 10.2 that, as I researched, turned out to be pretty common:
1) Printing. It was ridiculously complicated to get printing to work if it wasn't physically on the machine. And even the printer control wasn't part of the preferences which I thought was ridiculous. I had to go into "utilities" (a folder on the hard drive) to even attempt to set up a printer.
2) Networking. Networking just didn't work very well in a mixed environment for me. I eventually brought the iMac to work and was in the ridiculous situation of having to use a removable drive to move files from my PC to the Mac 4 feet away. I never could figure out why I couldn't connect to the network drives with Jaguar. It should have worked but didn't.
But Panther addresses both those issues. Printing worked both flawlessly and intuitively. Now, the printer setup is part of the preferences panel. I just typed in the IP address of my printer and off I went. No sweat. Windows networks are explicitly supported now in printing. The driver for my printer was easily found and available.
Same on network drives, it just works now. I didn't do anything differently, it simply works now. So I can access all my network stuff from the Mac which makes it much more useful.
Expose, as others have pointed out, really is remarkable. And it cannot be done on Windows at present. Not anywhere near as slickly. One would have to use layered windows like crazy to do it and it would be much slower, even on high end hardware. Apple doesn't have to worry about this feature being stolen on the PC until Longhorn comes out (at which point it'll be fair game). Apple definitely borrowed ideas from Windows too. The F11 key minimizing everhthing is akin to Ctrl-M and Ctrl-Shift-M on Windows. Fast user switching is pretty much the same as it is on Windows without the special effect.
The intelligence of Apple really comes through with Panther though. They KNOW that Windows XP doesn't have a compositer. That means it can't do fast, slick animations and changing of Windows. WindowFX (https://www.stardock.com/products/windowfx) is the closest thing on the PC for being able to do cool effects and I can tell you that it's a real pain to do even what it does let alone somethign like Expose or the fast user switching effects. I don't think Expose is a unique idea, it's something we wanted to do on OS/2 back in the 90s but being able to make fast thumbnails is just not possible. But credit has to go to Apple for actually doing it. Ideas are cheap, execution matters and Apple excuted on this idea. I will be annoyed if Apple and Mac users get all huffy WHEN Expose like features show up on Longhorn by Microsoft or third parties. Expose isn't an innovation, it is just MacOS X is the only OS capable of pulling it off (first person shooters weren't an innovation either, it was just a matter of when the hardware would make it feasible). So kudos to Apple for putting this in 10.3, it's a great feature.
The new Finder is very nice. I prefer it to the old one a lot. But even with all this praise, I still feel a little annoyed that Apple charged 10.2 users $129 for what is, essentially, a service pack and a shareware bundle (expose). Sure, it's a great deal for 9.x users but for 10.2 users, it's a major bug fix. I could live without Expose, despite its coolness. Being able to print and access the network is key but those things should have worked in 10.2
My verdict is that with MacOS X 10.3 Apple has made their OS truly ready for prime time. I'll go so far as to say that if someday Microsoft makes it too hard for us to work on Windows that MacOS would be an attractive platform to migrate to if it came to that.