Proportional representation favours the Left no doubt, because this arrangement gives power to parties and politicians who are avtivist in stances, and in the postmodern West the type of activist politics people love is leftist. When MMP was instituted in 1996, this marked the time when it becomes harder for the conservatives to govern because arithmetrically, we can't compete with the Left on votes proportions (they have naturally 52% versus conservatives' 48%). The same thing happens to Mother Britain - since the 1960s it has been estimated the conservatives could best no more than 45% of votes.
In Canada, under the current First Past the Post system you have the Liberals in power 75% of the time. Had you used MMP, this would have meant the Liberals, in coalition with the NDP, being in permanent governance!
I asked you what you thought just in case you were a supporter. I am not. I use to be, until British Columbia voted on whether to adopt it. The more a looked into it, the more I realized it would result in the left allying together and keeping conservatives out of power forever.
You are right. Liberal support of 30% plus Bloc of 10% plus NDP of 18% = 58% vs 41% conservatives (if you lump the greens in with the CPC).