I personally like GHK a lot better than WE, I had the choice, and after firing both, the GHK is definitely a cut higher in terms of recoil and noise, it kicks hard, and is also very LOUD.
One thing I did notice when firing is that the gun like the spew gas out from the front when firing extended full auto, not much, but enough to make it look awesome, like the barrel's very heated.
No news about the PDW mags yet, but I'd imagine they would come out with them later. Though I personally prefer STANAG mags.