Advantage of using resolve is that you
will have the data coming first before the template appears.
Let me give you an example where resolve can be used. In case of
getting google-maps with respect to geo location. If we have the
lat and lat through geolation first then we can use that in
controller to build the map. On the other hand if controller loads
then first the map will be loaded as geo location will take time
and then again we have to rebuild the map.
You can read about state provider and all its events at
https://github.com/angular-ui/ui-router/wiki
Thanks
Gaurav