It's not better or worse just different. The ACRX system is not going to move as much oil away from the motor as the DC Performance system. This is not a good or bad thing but will require draining more often. This is due to the connector at the PCV system and drawing out of the valve cover. The other valve cover vents to the air box which will still move some oil through the engine as well. The good is as you mentioned, it is still emission legal.
The X system does not pull any of the oil back into the intake and uses ports on the upper part of the valve cover that will help the system pass less oil out of the motor. It will still need to be drained but not quite as often. It is not emission legal. I am going with the X System but I will no longer be driving my car on the street. I like the DC system if the car is still street driven and emissions is a concern. If you have an aftermarket PCM (which you don't) then it really does not matter if the system is emission legal or not as the PCM is "for off road use only" anyway.
Why is the ACR-X catch can better than the air to oil separator that DC Performance sells? The DC solution doesn't vent to the atmosphere so it is emissions legal. Here's a pic of the DC air to oil separator in my 09 ACR.
Believe the DC setup is basically a catch-can....I have a similar system in my Jeep SRT 8 and it does "catch" considerable oil....the X system has a canted bracket designed to fit the Viper....I say this in case someone tries to retro-fit the same brand separator.......