For new customers, the advantage is that they can get the same kit (say body + prime + open telephoto zoom) that weights a lot less, so it's more likely that th

For new customers, the advantage is that they can get the same kit (say body + prime + open telephoto zoom) that weights a lot less, so it's more likely that they will take their kit out. For existing customers (like you), the disadvantage is that they may have to throw their kit away and start over, for some advantage in weight and in body technology, but need to pay a lot of money too.