Here the district heating is substantially cheaper than a gas furnace, at least in operation. I believe you have to buy the infrastructure and pay for the pipe that goes from the nearest joint to your building, though.

We don't do per-apartment heat exchangers, but rather one per building, typically with shared hot water radiators across all units in the building. Heat consumption is either estimated by a air/radiator temperature difference integrator on the radiator, or an electronic flow meter+temperature differential sensors on the unit's connection to the central hot water loop.