I use both. Each have their perks. Neither is the "wrong" choice.
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For the record, some of those around you will be annoyed if they have to listen to the thing beep at you. The rest of us will strongly consider making you part of a brand new artificial reef if we have to listen to it.
That's hardly a foregone conclusion, and there have been plenty of threads addressing that specific issue. Suffice to say that knowing how many PSI you have left doesn't change the PSI you have left. My take on it is throw the standard SPG in your bag along with the requisite tools if you must, so you can swap between dives. Otherwise, get over it or stop diving AI. There isn't a shred of evidence that one is inherently more reliable than the other, and you don't see anyone saying 'Of course, whenever you're using one standard SPG, you must have another standard SPG as a backup."
O.k., let's say you are deploying a SMB @ a safety stop and need to monitor your depth and time while using both hands to deploy the SMB.........What do you do?
I'm now switching over to spg and ai wristmounted computer.