Quick Answer: Is eSata Hot-swappable? Yes, if your motherboard supports it.

eSATA, the e is for external - meaning that the cabling used is meant for being outside of the computer chassis.

Many external hard drive casing kits will feature USB 2.0 connections along with eSATA connection.

The hot-swappable feature is only available if the motherboard supports the eSata hot-swapable functionality.  Current motherboards do as do newer models.  However, drives with older SATA connections will not support plug and play, instead you'll need to shutdown the PC and swap the drive and power the PC back up.

Another option if you'd still like to have the eSata functionality is to purchase a eSata controller card.

Are there really benefits to eSata over USB 2.0? YES, eSATA reaches transfer rates triple those of USB 2.0 and Firewire.  And there is no need for the connection to be translated before data send/receive as its directly connected either to the motherboard or the controller card.