This one is tugging on the "cool" factor and not the "need" factor. Police Agencies have been working for years to bridge the sidearm to long-rifle need for quite a while. There have been many guns like this one that never made it off the prototype stage because of funding, or capability it lacked. This is another in that category IMO.
I shot it and was equally unimpressed. Muzzle rise was much better than the typical Uzi/Uzi Variants. The accuracy was about the same.
There are already sub-guns in a multitude of man stopper calibers. The UMP in .45cal, MP-5 in it's .40cal variants. AR-15 platforms that are being created by companies that are the same length as a fixed stock MP-5 in 5.56mm to 7.62 with excellent reliability (shameless plug for the brother's company).
No need to reinvent the wheel or plug away at creating the next tool. Hold what you got and get proficient with what you have on hand. I'm pretty good at clubbing you to death with a pistol should it malfunction (training guns don't fire, but they still hurt).
Maybe should have just stuck with the "Shot it, it sucks!"
__________________
http://teamrwb.com/
"Let the blood of the infantry flow through your veins,or the blood of the infantry will be on your hands."
- GEN John A. Wickham, Jr. speaking on the responsibilities of MI soldiers.