As to the Heizer, I almost think of it as a modern version of the FP45 Liberator...a one shot deal to a get a more viable firearm in an occupied scenario. I think it's interesting, but not something you'd want to run 100 rounds through at the range.
Now, there are a lot of misconceptions of the AR or AK styled pistols. These, I find intriguing and far more functional than most give them credit for. What they have become are pseudo SBRs without the NFA and cross-state-line hassle. I've been quite surprised by the ease to accurately and rapidly engage targets out to 100-150 meters with these "pistols". The rifle calibers are a little overbearing with muzzle flash, but having used a 300 Blackout with suppressor really shows the value.
Moving on down to 9mm type "pistols", they provide even more functional and versatile, especially when suppressed. If these are modern-day mare's legs, they are far more capable then their big-screen historical counterparts.
ROCK6