I like the MPX. It makes a great host for an SBR or if the pistol brace fiasco is over as is. The biggest negative is the price of magazines. About $50 bucks a pop.

If you are looking for a pcc a Ruger takedown PCC with a magpul stock is pretty darned hard to beat. But it dies have a 16 inch barrel. Takes both block and river pistol mags using an adapter.