More and more SEOs are using separators like pipes, dashes, commas, etc when writing title tags. (Exclude underscores from the list, which are used as concatenators.)

Which of these separators perform better?

From time to time some SEO “experts” and their cheerleaders promote the idea that a particular separator performs better over others. See the following link:

And that is despite the fact that Google’s Matt Cutts has mentioned in two different videos that there is no real significative advantage of using one over the other. These videos are available at the following links:

My take?

I would like to see an analytical study supporting the facts. I believe this is reasonable to ask. Don’t you think so?