The USA is a republic, with a presidential head, while Canada and Australia share a decidedly more British model. The president is a directly elected office, while the Prime Minister is determined by the party leadership, and it is possible to be prime minister without a seat. Both Australia and America have elected senates. In Canada, its appointed. The American president faces primaries run state by state, and makes the actual election campaign run well over 12 months. In Australia and Canada, party leadership is appointed by party faithful usually well before any election campaign. In America, the Senate representation on a state by state basis is equal. In Canada, Senate numbers are based on provincial population. In Australia, votes can be cast on preferential basis- don't ask me how the system works, I mistrust it, while America and Canada use first past the post. In Australia every citizen of age votes by law, in the other two, you can if want- or not.
So, it sounds different right? Apples to Oranges? Can't make a comparison? Wrong.
Because of the nature of politics, consider:
The presidential race is down to 2 people in the US, the selection of either the Democratic Party or the Republican Party. In Australia it's down to the Labour party or Liberal/National party coalition selection. In Canada, Its usually between the Conservative Party and the Liberal Party (Jack Layton's rise of the NDP to official opposition status I believe has as much to do with election weary Canadians and the Liberal party's responsibility in calling it at least as much as the Charisma of the late leader. Mulcair, his replacement, I suspect was a poor leadership choice).
Each opposing side puts together a brief of policies during the election in which they believe will win the the majority of votes. Everyone knows the brief is pointless, and few if any promises will be kept. Because the information made public previously was inaccurate, or some crisis will arise which promptly sweeps everything else to the side (GFC for instance).
The election itself produces very like personalities in the candidates. A classic example is the 1999 American race between Gore and Bush- so alike in form and policy one needed a split screen TV to tell the candidates apart. This also seems likely in the upcoming Australian election, a conservative labour leader facing a labour leaning LNP coalition candidate. Who will it be? Speedos (a reference to Tony Abbot pulling a "Stockwell Day") vs the Backstabber? Is this even a choice?
Tony Abbot in Speedos
Stockwell Day in a Wetsuit
Southpark had it right. Every election leaves a one a choice between a "turd sandwich" (complete with pickle) or a "giant douche". The only winner is the candidate who actually wins. The voters always lose.
Its always apples to apples.