TheOptimizationIdiot - 10:07 pm on Mar 12, 2013 (gmt 0)
Due to the "debate" I'm running tests on this right now, not with a lang. variation, but with page variations declared as alternates and canonicals.
I'll do my best to remember to post results of the testing here. I don't "do" different languages on the main site I'm working on, but do "do" very similar alternate pages and I'm running some with a canonical and some without, so like I said, I'll do my best to post results and hopefully at least be able to "give people a direction" to look for an answer to the question.