Home defense they are great, same for close quarters, but for shtf unless you have it SBRed it loses its appeal personally. Because if I have something with an 18 to 20 in barrel I want to be able to engage targets at 200 yards minimum with it. That being said I own a PS-90 and if you had the accompanying 5.7 pistol then only needing one type of ammunition would be an advantage.
According to the gun designer of The Matrix.
Larry & Andy Wachowski: Who uses a .50 Desert Eagle?
Gun Designer: A wanker.
Wachowskis: No, who are they made for?
Wachowskis: Our wankers in this film want Desert Eagles.
Designer: Your film.