By and large, I think the Parliamentary system has many advantages, though NOT so much in the UK, where the ruling party is the one that merely has a plurality, and there are three major parties: Tory, Liberal and Labour. Unlike the French presidential elections, there is not a runoff when no one gets less than 50%. If there is a vote of confidence and the ruling party fails to win, then elections are called. Also, the ruling party cal call elections when it wishes. Canada has five parties that have seats in Parliament, plus two independent seats. The main parties are the Progressive Conservative, Liberal, New Democratic, Parti Quebecois and Green Party.
The Senate in both Canada and Australia is not based on particular provinces as it is in the US with 2 senators per state.