First of all, this guy knows how to have some fun. But who is he and how does he have access to all these weapons? I’m afraid we are going to find out that he is the son of a Russian Drug Lord or the like some day.
Realistically this seems like an awesome weapon, but the size and weight become an issue if you have to be mobile.
I’d say your better off in terms of weight and bang for your buck with a smaller fully automatic machine gun if you have to go solo. On the other hand, if you’re lucky enough to be part of a larger squad of survivors, where you can afford to have one member weighed down with a specialty weapon like this.
Obviously it will clear a room with ease, and open up doors for you, which could be very useful, and if you are lucky enough to be able to stock one in your safe house, go for it – on the other hand, if you are going to have to move solo or with one or two others, I’d pick a smaller, lighter weapon and carry the extra weight in ammunition.