Maybe it's just the contrast with having to struggle with Windows 8.1 over the last four days, but I really like Mavericks. When you use a computer every day it is the nearly imperceptible things that make the experience enjoyable or something that frays the nerves. What Apple generally delivers is stability and reliability, and Mavericks is no exception.
This application is still as problematic as it has always been. Since 2009, across multiple versions of OSX I always have to make sure the app is off and my machine actually shuts down. Otherwise I'll open the lid to a resume situation where my battery is dead because OSX got hung up on the Mail app while trying to shut down.
That said, it's still the best email app I've used on on a desktop OS. I don't know that I've ever used a "good" email application except on the iPad.
I won't rehash what basically the entire Internet has already said about iTunes. It's awful, will probably always be awful, and if you've bought into the ecosystem you're doomed to continue using it.
In iTunes defense, I've never used even a decent media management application before. Everything I've tried is somewhere between the "stinks like poop" and "this makes my mind hurt" categories.
Like I said before, the new versions are pale shadows of what they used to be and lack a lot of functionality. If you can scare up a copy of the older versions or already own them, you're golden. Otherwise, you'll have to wait for the improvements Apple has promised.
The reason for this is that Apple rebuilt these apps from the ground up to be 64 bit, and getting them back to their former awesome will take time.
System & Resource Management
My 2009 MacBook Pro was given new life by Mavericks. Aside from the failing battery, it runs and handles noticeably better than before installing the update. Everything I do feels like it isn't leaning on the system as much and the laptop can just do more. That almost imperceptible lag between operations, saving, opening applications, and similar is shorter or just absent entirely.
With only a few very system intensive applications do I see the icon bounce on the dock or the spinning beach ball of doom. Everything just seems to go when I click it. Where I was constantly checking Activity Monitor to see what was slowing my machine down, I never even look now.
For me, this is huge.
For me, this aspect of OS updates is pretty important. The biggest weakness of some software and hardware manufacturers is not that they can't identify when they've done something wrong. The real problem is when they can't recognize when they've done something right.
There is a lot of what I like about Mavericks are the same things I liked about Leopard and everything in between.
Anything Apple adds to the OS, I can pretty much ignore if I want and stick to the core UI and means of navigating and organizing my apps and data. If I don't want to use Mission Control or Launchpad, I don't have to.
There was no pressure to update to Mavericks and Apple didn't lock my machine with a gray bar and a link directing me to the Apple Store. That's a big deal considering the very tacky way Microsoft has decided to "encourage" people to update.
Like Windows 8.1, Mavericks was advertised to be free. Given the work day hours I've spent struggling with Windows, only Mavericks lives up to that marketing.
I'm not bitter or anything.
I'm not bitter or anything.