Qualities of a good SOFTWARE LBO candidate?

Hey guys, was just curious what PE firms look for in a good software LBO candidate, with particular emphasis on things that would be different from a traditional LBO candidate. Will sponsors load up the company up with less debt, due to less cash flow, and rely on their return coming from more multiple expansion due to a higher growth profile than that of, for example, an industrial company? Are IRRs any different or do they still target 20-25%? Are these often very mature or even declining software companies, or can they still be in very high-growth phases?