Wil Harvey said:At 10th level, you can make a 50 ft. DD away. Not that great, right? But you also leave behind a major image of yourself [.....] you're now 170 feet away from him when he realizes you're gone.
Useful if you're playing a solo game, but if you plan to continue the fight and help your friends beating the enemy, you can't go too far; much more useful to become invisible, move behind your tanks and keep on blasting the enemy covered by your frontmen, IMO.