I purchased an OTS Guardian last October (about four months after becoming certified) after nudging from a dive buddy and seeing his mask. I liked the idea of keeping my whole face warm as we are in Indiana and dive mainly in quarries where temperatures at the bottom can easily be 40 degrees or slightly lower(fahrenheit, mind you). I started with the SDI Full Face Mask specialty to give me some pointers on clearing, removing, and replacing the mask. I do not think it is necessary, but it certainly doesn't hurt. The worst part, I believe, of having a full face mask is that losing your mask results in losing your air source and vice versa. If you think you can handle that, then continue on.
I love the much wider visibility that I get from the mask--and no fogging! No more defog! I recently got back from Hawaii where I dove it on two dives. I unfortunately had the chance to compare it to my Oceanic half mask when on my two dives on Monday resulted in a splitting headache. I am thinking it was a combination of me being overly conscious of my air consumption and subconsciously attempting to conserve it resulting in CO2 retention. I switched to my half mask and Scubapro S600 second stage for my Tuesday dives and had no headache, though I had to do a lot more head turning to look around. I do not fault my full face mask whatsoever for my headache. I blame being a newer diver (35 dives at that point) and those being my first salt water dives.
I have probably 15 open water dives on the full face mask now and am comfortable with it. I initially had an issue getting a great seal around the right temple strap. It wasn't a significant leak, but there was a steady stream of small bubbles. My buddy and I both had the communications unit attached, and when he removed his, the seal was complete. I promptly removed mine and now enjoy a great seal on the mask. On the subject of the consumer-grade comms unit: It was fun to play with in the pool. It requires one to enunciate clearly and speak concisely, though once we practiced at it a bit, we were able to understand each other. I think if we played with the microphone position in the mask, we could have improved it even more. My buddy and I have done a significant portion of our dives together and feel that we can communicate just as well, if not more accurately, using hand signals and conserve the air that would have otherwise been vented while talking.
Maintenance on the unit is fairly simple. I ensure the mask is dried completely after each dive. I rinse it after every dive, especially salt water. I then towel dry the standing water in the oro-nasal cavity and the regulator cavity. It then sits open to air dry until everything evaporates.
Overall, I think if you are already considering the purchase, then you should go for it. If you can do a full face mask trial dive with your LDS, then you might consider that to be 100% sure you like the experience. It is a different experience to breathe from the mask, but nothing that one can overcome. My dive buddy who is a firefighter says it is similar to breathing from his SCBA, so he is right at home with it. The benefits of better visibility, no fogging, and, in my opinion, more securely fastened mask and air source make it worthwhile. It is much harder for someone to rip the full face mask from your face than it is a half mask or standard second stage regulator. The side benefit is if you suffer a bout of unconsciousness underwater, your air source remains available. It is a great piece of diving equipment and one I think I would not want to dive without now.
I hope this helps. If I can answer any more questions, I would be more than happy to do so.
