I just got a new Windows Phone today. In the first 2 hours, while I was setting up all my Apps, data and preferences the phone found several different system updates.
Each time I had to reload the phone, wait for the update to be installed and than, in 15 minutes or less, another update was ready to be installed. Even worse, I had to reload the phone three more times after it had just completed a reload because of Glance, Device Hub and motion data preferences.
I understand this is a one-time only event, since you buy it only once, but it was quite bothering after the second or third update: honestly I lost count, but for sure I did installed at least four different release of Windows Phone (and rebooted the phone probably ten times in total).