Was out with the owner Brant a few nights ago and we talked about this. He tried to keep it at par for as long as possible but the disparity has become so great that he couldn't any longer. 1.25 is still lower than the market rate though. Also he was getting Americans pretending to be Canadians to pay the lower rate (hence now only applying to Canadian airlines) and drivers taking US dollars, changing them into Canadian at the cambio and pocketing the difference.
We have always used USA Transfers and pay in advance using paypal. Makes it easy to hop out of the van with just tip money and inside to start our paradise.
As a Canadian, I would highly recommend Pesos this year. We got them before we left at our Credit Union. $1 Can = $13.3 Pesos. It was a lot cheaper than US which we usually take to tip with.
We're actually considering a mix of Pesos and US this year. Apparently Pesos are also better for the locals as well.