I built my wife a lightweight AR-15 for Mother's day. I had a complete lower assembly and put a lightweight upper on it including the ohhunt 12" rail. The rifle uses a 16" pencil barrel, a lightweight BCG, Polymer upper assembly and birdcage flash suppressor. The complete rifle with a RDS weighs only 5lb 12oz.
The ohhunt Super Slim Lightweight Free Float M-Lock Handguard really makes it look great! It's easy to hold on to and and has a positive clamp that won't come loose. If you're looking for a lightweight rail, this is one of the lightest and best looking I've found for the price.
The only con I found was after I torqued the barrel nut down and installed the gas block and tube the tube would not fit through the barrel nut to go into the upper. After about 5 minuets with a Dremel that issue disappeared! I had no problem with the barrel nut fitting my barrel nut wrench.
I'm seriously considering buying several more 12" and 15" ohhunt rails for future builds and replacing 2 15" rails on existing builds to lighten them up.