I often get involved with those arguments so I might as well here too
For me it is a bit of both. I have a hardwired Shearwater on a JJ CCR. That choice was about the screen mostly. The competition at the time was a monochrome LCD and I was not about to spend £7k on something with a UI from 1983.
So I need a backup for that, at first I used the Helo2 which I had been using for OC diving. But to half properly track the deco I need to set a couple of extra gases and change gas as I ascend. That is a bit of a hassle. So I decide do to blow some money on a CCR capable backup. The choices were another Shearwater, a Suunto Eon Steel, or an OSTC. They all have advantages and disadvantages. The Shearwater is exactly the same UI as the CCR controller, less thinking is good, but the screen isn’t not so good as the others. The Suunto has a very nice screen but can’t be set to extreme kamikaze mode for use in the case of a CO2 hit. The OSTC can do that, has a nice screen but the UI is different. Also I read their code once.
In the end it came down to the UI being the same. If I have to bail out due to a CO2 hit I would still have the primary electronics to do a GF100 based ascent. The Suunto might bend but so what. If the primary electronics fail I could ascend on any of them, even a Helo2, as there is no rush.
Also, since Shearwater have the best marketing I know I can always sell it for good money. Like Apeks regs, Halcyon wings and a number of ther bits of kit there is a set of people who have read they are the dogs b******ks and will want to buy them.
Open circuit I am mostly diving with divers who have a Suunto. I usually dive the Perdix on one arm and the Helo2 on the other. I use the excellent ‘Dive Log’ app on my iPad so the Perdix is now my main logging computer because the Bluetooth works very well. The Suunto will left me know how much NDL/deco my buddy has (I set it to their mix) it is most unlikely I’d put them into deco but if I am on Nitrox and they are not it could happen.
Since MultiDeco runs on my iPad it is easy to plan GF dives on the boat. For the Suunto I need a laptop too.
Price. I deal with a lot of new divers. The thing I want is to have them continue to dive once they qualify. That lets us fill boats and provides buddies. The chances of that are not improved by a computer costing £812.60 ($1144 USD).
Gases. Having a computer, of more or less any algorithm, which allows more than one gas on a dive is an advantage. This allows an intermediate diver to take an accelerated deco course without entirely relying on tables. This doesn’t need to be the £812.60 computer above, most makes have that available one bump up from entry level.
So all in all, the algorithm matters to me for matching, but usability and features like the screen or Bluetooth are more important.