I decided to update my macbook air 11″ with 2gb of ram to OS X 10.8 mountain lion. So far the impression is, that it is faster in speed than 10.7 lion. I have not made any use of the new features like notifications. Which is supposed to intergrate social media into Mountain lion. I found all software I use could run on Mountain lion. I did have to update a few of these to a later version, but that was just some time, it took for this to happen via the App store.
Seems there is a issue when you install the xcode developers tools from the Apple app store, it does install the command line tools, if you want to run apps like homebrew etc. You do not need the command line tools to install homebrew, but you do need the command line tools.
To install the command line xcode tools. You need to start up xcode, the go file > preferences > downloads and the click on install Command line tools. Its that simple. Just sit back, wait for about 100mb to download and install.