Let me start by saying I have dove FFMs (AGA mask) for about 8 years both professionally as a Fire Department Rescue Diver and also recreationally. I own an AGA mask, and have used it for wreck diving in NY, and some fresh water diving in quarries around the NE. I have used the FFM for deep dives that included switching gases for deco and also for playing around with a single tank in shallow water while working on boats in the marina. I also dive with standard regulators and a mask, which is my prefered choice for penetration wreck diving. So I will say confidantly I have an idea on this subject, and can speak from experience and not just what I have read elsewhere on these boards.
$$$$ -
A FFM is an expensive item that should be at the bottom of your list of equipment to buy. A FFM will run you anywhere from $400 up to $1000 depending on what brand and options you want. And that is with out coms. Add $200 to $500 for a com set, per mask.
You will still need to buy a first stage regulator and a standard octopus as I haven't seen any FFMs that come with a first stage (except LDS packages), plus a standard face mask for backup. Oh and most FFMs require a high performance-high flow 1st stage regulator. so your sherwood piston probably won't cut it...
If your diving in cold water you'll need a special hood that will seal with a FFM because you can't put your hood over the maskstraps, so it must have a double sided face seal. (a latex hood or Whites makes a double sided neoprene just for FFMs). If you try to put the FFM on, then your hood over it, you'll never be able to pull the mask off in an emergency...
More complex to use... safety-
If you have a problem with a standard regulator while under water, you just let it go and stick you octopus in your mouth, blow out to clear and your back in action.
With a FFM it gets a little more complicated.
If your mask has a problem you need to take the mask off by pulling it up off you face, then you put your octopus in your mouth, clear and start breathing with out a facemask while you get your standard facemask ready(which you always need to carry with you, either around your neck facing-backwards or in a pocket) You get your mask in place and clear that too, now your back in action with a big clunky FFM swinging around on the end of a hose.
If your standard facemask leaks, no problem, you wiggle it back and forth to seat it a little better on your face, lean back your head and blow out through your nose and its fixed. A FFM is the opposit. You need to fix the seal, then lean foward to blow out the water through the exaust valve. One more thing to remember.
A complete flood (ie knocked loose) is much more complicated in a FFM. A complete flood takes away your breathing and your sight, whereas a regular mask will only take one or the other. So if your reg is knocked out of your mouth you either grab your reg (or octo if you cant find the primary), stick it back in your mouth, clear and breathe. If your standard facemask gets knocked loose and floods, you can still breathe, so you set it and clear it. But with a FFM you will loose both sight and breathing at the same time, and if your in cold water, will hit your face like a blast of ice water. This can cause all kinds of problems if you didn't aclimate your face to the temp before you put your FFM on. The cold shock can cause a full blown lyrngospasm or just a quick gasp and a mouthfull of water, either way your going to be in trouble, real fast and will need to have your wits about you if you want to survive this.:wacko:
So to re-don your FFM you pull it off and go to your octopus for the moment (not your backup fackmask, just the octo). You loosen all the straps, take one last big breath of air from your octo and spit it out while you press the FFM to your face, holding it tight in a face down position you press the purge botton on the reg to clear the FFM. once the water is out of the mask, you can breathe while you pull the straps over your head and tighten them. But if you don't hold the FFM tight untill you get the straps tight, the FFM will flood again and you'll need to purge it again. Depending on the FFM and how good a seal your holding, it can take anywhere from 10 to 30 seconds to fully clear a FFM, all the while your holding your breath. This is probably the most difficult task to master in a FFM and gives people the most trouble when learning how to use a FFM. Some people (who shouldn't be using FFMs) who completely flood a FFM will not even try to re-don the FFM while under water, but just go their octo and facemask to continue or surface. But if you're just at the begining of your dive and a buddy kicks your mask loose 110' under water, what are you gonna do??!? go back up to the surface and rest your mask and go down again?!?!?
This is also a skill that requires BOTH hands to do, so if you've got that $400 metal detector or the $180 super hid light in your hand you'd beter clip it off quick or just drop it if you're on the bottom.
field of vision-
A FFM drasticly reduces your field of view downward, so if you need to see your BC inflator or your octo to use it, a FFM is not for you. With a FFM you learn to use standard locations and feel of your accessories to find them. I know my lift bag is always in the same place, my reel is always in the same place, I can find my octo with out looking, my BC inflator is always at my fingertips when I need it, etc, etc. I am amazed how many divers I see actually looking for their equipment when they need it.
A full fack mask is an advanced piece of equipment that requires training by someone very familiar with their operation. It's not something you can learn how to use in one or two "pool" sessions. A good instructor will show how and why you need to aclimate your face to the temp under water and why you need to be proficent in all FFM skills to the point that it becomes second nature. Like blowing out through your nose to clear your facemask is second nature, we don't think about it we just do it. FFM skills need to be this ingrained in your head so when the s^&t hits the fan, you don't need to think how do you clear your FFM.
A FFM is something that can be very usefull for various reasons (coms, diving in contaminated water) but in the hands of an untrained diver it can be confusing and deadly.
The Rescue classes I've taken all start with a skills check and the hardest one for everybody is the FFM to octo and then go back to the FFM, all while underwater. This is something I practice every time I use the FFM. If I'm at dutch springs, I'll sit on one of the under water platforms and do this five times or till I'm completly comfortable with it, If I do a wreck dive in the atlantic, I'll switch to my octopus after my deco is complete but before I go up the last 15 feet. Then I'll switch back and surface.
Oh and one more thing, you can't vomit in a FFM... this seems kind of a gross statement, but I was sick one day out in the atlantic 80 feet under water (a stomach virus I later found out). Well I felt it coming up and ripped off the FFM and shoved my octopus (poseidon cyklon) in my mouth as I barfed. I coughed and barfed again, each time rinsing, clearing the reg and getting a breath in between coughing fits and gagging. But when finished I felt better so I put the FFM back on and finished my dive.
For the average rec diver I think the money can be better spent on other gear. And if you're still not sure, try one in a pool before you buy it, and get a proper class on it from an instructor who uses one on a frequent basis.
