I think in general terms, INZ serves a first-come-first-serve practice, but there ARE priorities for different categories or scenarios. In the meantime, immigration officers are accountable for handling a number of visa applications allocated to them, which they have to inspect in rotation every day. Personally I don't think waiting for a few months is too long to suffer compared to the processing time in Immigration Canada, where applicants have to wait for a couple of years before the decision is made.