This is a bit of an "other crap exists" argument.
I'm sure whatever political party you're voting for, that has had a term at the provincal or federal level, has had as many if not more examples of poor financial handling considered the NDP has a very small track record in comparison to the Liberals and Conservatives.
I'm not vouching for any political party but if your claim is that the Liberals or the Conversatives have not majorly mishandled the federal budget from massive increases in deficeit, privacy concerns, businesses leaving the country, etc. then the argument the NDP would do worse because your example is Mannitoba is not a very strong argument. Even comparing a provincial budget to the federal one is exponentially more complex and would by no political party be strategized in the same way. Financial analyst will rarely compare these two for obvious reasons. Even the way the budgets are balanced and due process at a provincial and federal are so different that applying if 'x' then 'y' logic would be ludicrous. You would, for starters, need to look at the overall federal policies proposed by the NDP to start estimating any ressemblance of how they, or any political party, would proceed with a federal budget. Keep in mind that if you review the Conversative and Liberal provincial budgetary plans for BC, they are night and day against the federal policies currently enacted.
Furthermore, if your source and method of educating yourself on the matter as a resident of BC is an Editorial Opinion from the Winnipeg Sun that nearly ends with, "It’s all signs of an arrogant, tired government that has little sense of how to manage a province", essentially character assassination much like Fox News instead of actual political debate then there is little point of discussion. As soon as those methods are implemented there are serious conflict of interest and neutral point of view arguments to discredit your opinion regardless of how the 'opposition' performed or policy based arrgumentd introduced.
To put it in perspective, I've never voted NDP, but I am pro-political process which at any respectable level is not the Winnipeg Sun editorial section, character assassination, or making far fetched budgetary comparisons that most tend to avoid. If you recall a recent widespread attempt in California to suggest the Republicans were going to run the US the same way...