I guess it would depend on how many users are using the app and how often they are set to poll the numbers (how real-time the users want it), and how often the numbers change.. If you have a relatively rarely changing numbers, then polling them often would cause more load than pushing them. Also it might be a good idea to consider that there will probably be clients out there who (somewhat understandably) want to poll way too often to keep the notifications closer to real time. Real time does not matter to me personally, I don't know if it matters to other people.