When the Magpul concept was first released in PDF format, it showed different tail sections. One that stands out in my mind was a carrier for 40mm grenades. I believe it held 3 or 4. This isn't likely something us civilians would need (unfortunately) but the military aspect would be good.
Magpul has been ramping up a lot of products within the past year or so now. They've got the ranger plates, magazine followers, pistol grip, the 93a stock, which has been upgraded yet again to the 93Ar, and possibly a 93b version on the horizon. They have the regular magpuls, and the rail protectors/hand guards.
I wish he would focus more on the stock, due to the fact that a massive wave of business is heading his way on September 15.
But, if you want to pick like 90% of people do, the Magpul M93a* looks cooler then the other one.
-Steve