Suunto might lock you out but it will still properly calculate any stops that you might need to make to get safely out of the water.
That has not been my experience. About a decade ago, I got a Suunto DX for testing and also had a Oceanic Atom I was using.
I was on a deco dive and the Suunto had me doing a lot of deeper stops which I was obeying. At one of the stops, I could see my richer deco gas that I had stashed about 3 feet shallower and my Oceanic didn't have me requiring a stop at my current depth so I figured I would get to the gas and accelerate my deco.
The Suunto had about a minute left at the current stop I was at so I just went to the gas.
That was a mistake. The Suunto went into violation mode (under water on a dive no less) and no longer gave me any stop information. It was insane. I luckily had my Oceanic with me.
I personally only dive Shearwater at this point. For the diving I do, I really don't think any of the other mainstream dive computers are suitable for me.
I understand that a lot of computers go into a 24 or 48 hour lockdown after surfacing and after a violation. I won't argue if that is right or wrong (but I do dive Shearwater computers which don't do that).
However, to go into lockout mode while on a deco dive is absolutely unacceptable IMO. Go ahead and penalize me or alert me or whatever, but to lock me out during a dive is ludicrous.
I will never dive a Suunto again.
- brett