Those rifles are a lot of fun. I used to own one of the SOCOM IIs with the quad rail on the front, but sold it after I bought an AR-10. I think you made the right choice in skipping the quad rail. It didn't do much beyond add weight out on the front of the rifle and scrape off skin when I wasn't careful. Besides, there's almost no way anyone would use all of that rail space. Better to put a small section of rail just where you need it.
Anyway, the rifle itself shot well and was very reliable. The muzzle break they put on those SOCOMs is really effective. I put a red dot sight on mine, but it always bothered me that there was no way to cowitness the red dot with the iron sights. Note that if you want to add any sort of optic, the stock design makes it necessary to abandon your cheek weld. Instead you're left with sort of a 'chin' weld. My advice to you is to just use the iron sights that the stock is designed for (they're excellent iron sights anyway). Have fun with the new gun!