My 2cents:
For me, SL ist THE working environment. I use my computer mainly for work. And SL helps me do it just the way I need. I do programming, designing, administration, scientific stuff, ... Everything is pretty perfect.
I bought a new Computer when Lion came out and I boucht one when ML came. Because I need to test my software on different systems. And buying a new computer is just the most hassle-free way to do that. They sit somewhere on my desk and are used maybe two times a month. They are testing machines. Working with them? Hell no!
There are some things though, which I would like to have in SL: Vertical window resize, the newest Safari without the upload-bug and maybe the new less-rounded buttons. But thats pretty much it. App store is ok too. Helps me find out what my competitors are doing. 🙂 But it's already there in SL, so why bother.
We'll see what 10.9 will be. SL had so many great features for me as a programmer. Let's hope 10.9 will be more like that.