Funny, I feel the exact opposite. The FreeBSD style(9) documentation suggests tabs because they can be customized to individual developers needs and they minimize weird diffs on the version control systems.
The real issue with that question is that it's impossible to answer. Even if you get a "spaces" person, try to get them to agree on the number of spaces. A coworker loves 2 spaces which is flat out wrong to me. Too hard to read. I've met people into 3 or 4 spaces. Then you get into where to put curly braces, etc.
Whatever you choose, it should be a standard for code whether at an open source project or a company.
I can't stand everyone using their own style. It's much worse than having to use a specific one.