Am looking at getting a rail system on my current build AR, its kinda going to be a .223 SASS and was looking at getting either a 13.2" larue rail set up or a Troy MRF 13.8" am kinda leaning towards the Troy because of the price, has anyone used them? are the great or just ok? and I got to pick up a low pro gas block

P.S. is going on a 20" barrrel