There is definitely some misinformation upthread.
This is a good start:
Dive Computer Comparison PRODUCT NAME PETREL 3 PERDIX 2 TERIC PRODUCT IMAGE BEST SUITED FOR DEMANDING DIVER DEMANDING DIVER DEMANDING DIVER KEY FEATURES Powerful computer with advanced feature set, bigger screen display, air integration, vibration […]
www.shearwater.com
Other points:
The Petrel 3 standalone is 1mm thicker and 2/4.5 mm wider/taller. But, for that, you get a 1cm (diagonal) bigger screen, compared to the Perdix 2. So, not really “bulkier” (or not very much at all - unless you buy the Fischer cable version).
The Teric and Petrel 3 both have OLED screens. The Perdix is LCD.
I have owned and dived together a Perdix and Teric. I think the Teric is just as easy to read. I think that is partly due to better contrast from the OLED screen and partly from more efficient use of screen real estate. And that is with the Teric in Normal, not Big mode. And I wear readers, too.
I would assume the Petrel 3 would be easier to read than either of the others.
The Teric compass blows the others away. The only thing easier to navigate with is a NERD.
I strongly prefer the Teric 4 button interface. The 2 buttons on the others basically gives you Down and Enter. The Teric has those plus Up and Back. You CAN use only the lower left and upper right buttons on the Teric and then the menu navigation works just like a Petrel/Perdix.
The Teric is much less likely to catch on things while you’re wearing it. For me, that mostly translates to when I reach between my rig and the one next to it on a boat bench for any reason. But also donning or doffing a harness or reaching between my body and deco cylinder to access a thigh pocket.
I’ve had accidental button presses on a Perdix. Usually from dry glove rings. I’ve never had accidental button presses on a Teric.
On multi-day trips I dive with 2 Terics, in case one craps out. They are small enough that I just fasten my backup around my low pressure inflator and shoulder strap. Totally out of the way and I never know it’s there. But, I could easily see it if I wanted to.
You can use an AA in a Petrel or Perdix. If yours dies and you don’t have a spare they are easy to find..The Teric is rechargeable and you can charge it with pretty much any wireless cell phone charger. Those are more and more easy to find just about anywhere nowadays. If I start a week long dive trip with my Terics fully charged, I will generally recharge them once about mid-week, just to be safe. Fortunately, one charge lasts long enough that even if I get to mid-week and then forget to charge them for a couple of nights in a row, they will still make it.
All 3 are equally capable for technical diving. They all support Trimix, multiple gases, and CCR mode. I use my 2 Terics for OC red and tech dives, and 1 Teric as a stand-alone backup on CCR tech dives.
They all support Bluetooth for wireless download of dive log info and upload of firmware updates.
I prefer the Teric. But, if I were buying a brick computer, I would give some serious consideration to spending the extra 13% (USD$150) for a Petrel 3 for the bigger, better display. Don’t know if I would, but I would definitely think hard about it.