As a developer, do I need Mountain Lion? I'm a college student and aspiring Apple developer. As such, I am trying to find an intel Mac Mini for as cheep as possible. I've noticed that there is quite a price gap between the models that can support Mountain Lion (late 2009 and later), and those that can't. Since Lion supports the App Store, do I really need Mountain Lion?
Mountain Lion versus Lion is one thing, but it's worth considering that, with Apple's apparent intention of releasing a new major version of OS X every year, a machine that can only run Lion will rapidly fall far behind the baseline. This may make it hard to develop against new SDKs that require the latest version of Xcode.

Buying an older Mac mini may mean saving money now only to have to spend it sooner than you'd like to remain productive.