Read all of the above, its easier to reply that way. I've already stated that both DCs ideally should be using the same algorithm ALTHOUGH not really a problem as both will start simultaneously at the beginning of your dive and differences between algorithms are not so extreme."If someone is so worried on backup instruments and safety" it should be resolved by educating him/herself on basic deco principles not by investing in another DC.
For the same profile, different computers or the same computers with different settings will give you different information so how can you say that they are accurate? Precise yes but which one is correct?
I have nothing against DC and you are right that a cheap basic one is a good choice but, here, we are talking about diving with a watch and yes, even if you don't agree, a watch is also a good option to monitor your diving parameters.
And yes, we disagree. A watch is not the best option as practically no one follows a predetermined diving profile set in advance using the US NDT like in the earlier days. This is an open forum and people can say whatever. IF you belong to that small category that really plans your dives in addition to using a dive computer, my answer is the same as previously: Congrats.