PFL. Easily one of the most comfortable masks I've ever worn, even if it's a bit lacking in features.
The GP-6 is nice, has the nice feel of a GP-5 but you can actually talk and hear with it on. Wouldn't recommend using their filters tho xD
PMK-3 or ROU.
The look & Unexpired Filters are great
Shms, forward facing eyes for optics, thinner rubber on the ears, and voice diaphragm. It also uses a hose which is cool, and looks like a skull.
What do you think?