I miss it in a nostalgic way but I definitely don't miss using it! I'm hoping 10.10 is named 10.10
Don't miss it.
Have been using OS X since 10.0.
10.0 and 10.1 were barley usable for real productive purposes.
They were fun, no doubt, and a very fresh breath of air after System 8.
But I wouldn't want to go back.
It just felt ahead of time, and I'm still amazed how little the UI has changed structurally.
I miss how revolutionary and exciting OSX was at the start. It was incredible and cool and extremely different from every other OS out there. It was truly deserving of the term, "revolutionary." That was also a very exciting time, in general. Apple was blowing the competition out of the water with bold designs and new ways of thinking about computers and operating systems.
How was it revolutionary? Most of the core technology came from Next/Unix. I mean, until Apple adopted Unix, they hadn't even managed to make a proper multitasking OS (as, say, Commodore had done with the Amiga more than a decade earlier). OS X was Apple playing catchup.