I've had/have the following helmets in this category over the past few years:
MET Parachute
Bell Super 2R
Bell Super 3R
Giro Switchblade
Bell Super DH
Fox Proframe
Also a Giro disciple (regular DH full face). Thoughts on each:
MET Parachute: very comfortable, light weight, very goofy looking. Poor chin/jaw coverage, still got face rash when crashing with it twice before I totaled it.
Bell Super 2R: loved the removable chinbar, great helmet. Needed to pull these plastic pads out of the inside to make it fit. No huge crashes, wanted a more secure feeling helmet for Enduro racing so got a:
Giro Switchblade: this helmet sucked. Very uncomfortable to get on, heavy, hot. Took a digger wearing it at a bike park and the chin bar came off (on review the plastic clips on the upper shell where the metal arms of the chinbar clip into bent and broke) allowing my face to drag on the ground and get some good rash. Guess it saved me from a broken jaw though. My least favorite of all those I've tried.
Bell Super 3R: got after my foray with the Giro. No huge difference from the 2R. Good helmet overall, got dinged up from low hanging branches, etc. over a year of ownership so replaced it with the:
Bell Super DH: noticeably larger and slightly heavier than my 2R/3R. Much more secure feeling with the chinbar on but also rather uncomfortable. Chin bar noticeably more difficult to attach than with the 2R/3R. Use this mostly for my halfshell now but still bring the chinbar along if doing a big climb/big descent type ride. But uncomfortable to wear in full face mode for prolonged periods so got the:
Fox Proframe: favorite of the enduro/light full face helmets so far. Honestly I notice very little difference in ventilation compared to the Super DH in halfshell mode, and it's loads lighter/more comfortable/better ventilated than the Super DH in full face mode. Not as secure feeling overall as the Super DH, so I use my Giro true full face for bike parks or more gnarly enduro races.
Hope this helps. For what it's worth all helmets have done a good job saving my noggin when crashing in them.