Nearables advertised packet?

I understand nearables are advertising a custom packet.
Is the packet being detected by IOS using the core bluetooth and not
the core location, like eddystone?
Is there a difference permormance wise in the time it takes to detect a nearable
advertising the estimote packet compared with regular ibeacon?
Does it consume more battery to detect nearables with estimote packet compared to iBeacon packet?
If there is a time difference, what would be the time delay to receive a local notification for
an estimote packet, in average?