While talking to someone today he mentioned a concern about my team's "homegrown" software: that it would nickle & dime us to death compared to "more robust commercial software". I respected this guy - he was very bright and had a lot of successes under his belt. But I also felt that he was both echoing a common corporate perception, and was quite wrong.
I've run into this notion so often that I now plan for it: in the minds of many commercial software has more credibility than open source software, which in turn has more credibility than custom-built software. And since these perceptions are often held by those that control my budget - perceptions matter.