I have both of these firearms... I haven't shot either yet, but my plans are to SBR them before the end of 2015.
The POF/MP-5 that I have has two "minor" issue, the front sight is slightly canted and there is far more "wobble" when the magazine is locked into place than with my HK-94 carbine. I consider these two issue minor and will have them fixed when I send it in for refinishing since the factory finish is rather very poor... I knew about the finish issues before purchasing this pistol, so that isn't a major concern to me. The main reason why I went with the POF/MP-5 is that it has a swing-down trigger housing, like the original MP-5 SMG.
The CZ/Evo Scorpion, which I picked up yesterday, had immediate eye appeal. No noted visual issue with this pistol was noted. The trigger is rather stiff, but not to a point to cause any serious concerns. The only issue I can note at this point is that the safety lever is slightly too long when in the "fire" position and digs into the thumb on the trigger hand... I heard rumors that CZ is going to re-design the safety, so it should be an easy fix... I should note that I wear XL sized gloves, so my hands are slightly larger than average.
If I had to pick one and if SBRing it wasn't possible, I would go with the POF/MP-5 pistol, but I should note that it runs at approx. $1450.00. Plus, magazine options for the POF/MP-5 are far greater at this point, but depending on what magazine you go with, it can cost up to $75.00 for a HK factory magazines and $30.00 for the POF made magazines... Stay away from the Korean made ones at all cost!!
If I had to pick one AND SBRing it WAS possible, I would again go with the POF/MP-5 pistol.
NOW!! if cost was an issue, CZ/Evo Scorpion pistol is a hands down winner and the cost of extra magazines are reported to be around $22.00 each... When they're available... I hope that CZ-USA will import many-many more to meet the demand for them. I'm hoping to purchase ten 30rd magazines in the near future.
I should note that both of these pistol are fine firearms, but due to their size and weight, they beg to be SBRed since in their current configuration, they offer no advantage over my Browning HP, Beretta M9 or my Glock 17 and 19 9mm pistols. With that said, they do have the ultimate "cool" factor and added value if any gun ban should raise its ugly head in the near future... If Hillary C. become the next President.
Both firearms where retirement gifts to myself and if you have the means to purchase both the POF/MP-5 and CZ/Evo Scorpion pistols, I would say buy both now. I'm sure that you are aware that MKE will be releasing their own redesigned MP-5 pistols within the next few weeks, but at about $400.00 more than the POF/MP-5, but every indication that the fit and finish on the MKE pistols will be far better than the POF made versions.
Good luck!!