I finally got to breathe on my TFX underwater yesterday.
I put my TFX/Ti2 Octo set on a pony bottle and dropped down to 60'. I had my M1 regs on my back mount doubles, so I was able to swap between all 3.
The feel of the way the TFX breathes is subtly different than the other 2. If I wasn't focused on it - i.e. I was just diving and paying attention to the reef/wreck/fishies - and for some reason didn't know what reg I was breathing from, I might not even notice that something was different.
To me, in the grand scheme of regulators, the difference between the TFX and 2 other top quality regs is just not very big. The difference between any of my 3 and some of the cheap, crappy, (probably poorly-tuned) regs I have used in the past is way bigger.
But, focusing on the differences, there were some that were easy to detect.
The TFX does feel like air starts to flow with no effort. The other two didn't feel like they required any effort, either - until I swapped between them and the TFX. Then, the very slightly higher effort was discernible.
Once the flow started, the TFX also feels different in the way it flows. As one would expect from the cam design in the TFX lever mechanism, the TFX flows less air when you inhale very gently. And when you take a big gulp, the flow ramps right up to match. An easy inhale gives an easy flow into your mouth. A hard, sharp inhale gives a big, high-flow shot of air into your mouth.
This is in contrast to the Ti2 and M1 in that, once they start to flow, they feel more like they flow about the same on an easy inhale versus a hard, sharp inhale.
It seems like the TFX will make it easier to breathe very slowly. That is something I struggle with. When I try to inhale slowly, it always feels like actual work to keep my inhale slow. Now that I've experienced this, I am really looking forward to my next long-ish single tank dive trip, where I will have time to adjust to the TFX and then see if it makes any difference to my RMV. I always dive with AI, so I have very detailed RMV data from every dive I've ever done. If the TFX makes any difference, I should be able to see it.
Something else I noticed about the TFX is it seemed like it REALLY wanted to freeflow when I took it out of my mouth. It would stop if I pointed the mouthpiece down. But, sometimes it seemed like no matter how carefully I tried to turn it back to normal or pointing up, I could not prevent it from starting to freeflow again.
Also, it seems like it must trap some air under the purge cover that slowly trickles out for a while after you stop exhaling. At first, I thought it was still freeflowing. I experiemented with inhaling and then holding my breath and watching the bubbles continue to trickle out directly from somewhere around the purge cover for 10 seconds-ish.
The ease it demonstrates in freeflowing, and having no WOB adjustment makes me think this will not be a reg that will work the best as an "octo". With no way to detune it in the water, I think you'd either have it freeflowing often during dives, or you'd have to adjust it to be de-tuned at all times, which kinda defeats the purpose of having a TFX.
After swapping around in a normal horizontal hover, I then experimented with some alternative orientations.
Being on my back, looking straight up, the TFX definitely breathed more easily. That was really nice.
I also tried being inverted vertically. I.e. standing on my head. The results here were surprising. The TFX seemed like it still breathed a little easier than the other two. But, the difference was completely overidden by how the TFX and the Ti2 both breathed noticeably wet. Every inhale was accompanied by just a little drizzle of water. The weird thing was that my M1 stayed totally dry in the same orientation. I could not detect any water coming into the M1.
I also have to say that the M1 seemed like it breathed just a little differently - in a "nicer" way - than the Ti2. I was expecting them to breathe exactly the same and I'm not sure why they felt different. Nor do I feel like I can really articulate how they were different. Maybe a little "smoother"? Or maybe a little more flow once it cracked?
I have had the M1s for something like 3 years maybe. The Ti2 is brand new. I have never had the M1s serviced, nor have I ever tried to adjust them at all (other than turning the WOB knob). So, all these regs are still exactly how they came from the factory. I have talked about adjusting the cracking on the TFX, but I have not done it yet. I wanted to try it exactly as it came from the factory before changing anything.
So, that's pretty much it.
The TFX is really nice. I like the benefits of the titanium. I like the breathing overall and the slightly easier breathing in "alternative" orientations. But, is it worth the price premium over a T3? Is it worth the price premium over a Z2? Only your wallet can answer that question. All I can say for sure (at least, "for sure" in MY mind) is that there are differences - but they are pretty dang small. The weight difference to a Z2 is small. The breathing differences are small. But, those differences ARE there. And, I will be keeping my TFX set. I DO believe it will be the last single tank reg set I ever buy.
As I expect my M1s are the last doubles regs I will ever buy.