The Vytec is OK for square profile diving with up to two gas switches. The deep stops and intermediate stops are somewhat lacking but I understand the new version has looked into this area. I found it annoying that it wouldn't show a time to surface on all available gas. The Time to surface would always be on the gas you were running at the time. Not very usefully and requires pre planning to know exactly where your at in terms of gas and deco.
The Vytec will not credit you for additional deep stops or for any time spent shallow. I once racked up massive deco due to staying at 10m rather than ascending to the recommended 5m. I had to bend it that day. Next problem is once bent it stays bent for at least 24 hours
If your thinking of computer deco the VR3/ VR2 is a quantum leap forward from the Vytec. however they wont let you use it when diving DIR so there is little point in getting one if you thinking DIR is the way forward.
However if you are considering computer deco...In terms of true decompression computers the new VPM based VR3 is the best on the market by a mile.
ATB
Mark Chase