I don’t have nearly the experience with FF rails that others here do, but I have two: A Troy MRF-C and a DD Omega 7.0, and am currently waiting on a DD Lite 9.0 for a Noveske N4 middy upper I just bought from Grant.
Both FF rails are solid hanguards, but I prefer the Omega to the Troy. The Omega is lighter and utilizes the original delta ring, with no alterations to the firearm at all. Virtually anyone can install an Omega rail, as it is that easy to install.
The Troy MRF-C requires no special tools, but since the delta ring is not used with this set-up, the included instructions suggest either cutting the delta ring off with bolt cutters, a saw or Dremel tool.
I chose to remove the front sight, gas tube, barrel and spring washer – to avoid cutting anything. Thus, a little more mechanical acumen was needed either to cut the delta ring or to avoid cutting it.
Weighed separately, the Omega is almost 3.4 ounces lighter, but since the MRF-C doesn’t use the delta ring or spring washer, they are almost the same weight when installed. The Troy is definitely slightly heavier.
Both are very solid, rigid and lightweight, but IMHO, I would give the DD Omega the edge.