Dont forget that with a Viper you will need an SPG that you dont need with the Cobra. Based on pricing from DiveInn there is only a $66 delta. I think that air integration is well worth $66.
Cobra $416
Viper $290
Suunto SPG $60
Total $350
Delta $66
While not everyone prefers air integration I think that its great for two reasons:
1. It provides estimated remaining air time, which while not a substitute for monitoring air pressure, is useful during a dive. I especially like being able to compare the remaining air time with the remaining NDL time. It also allows me to track my surface air consumption rate.
2. I like having everything attached to my BC (with the exception of mask, fins, and gloves which cant). This reduces the complexity of getting ready for a dive. While putting on a wrist mounted computer is no big deal, its one more complication I prefer to do without. Its also one more thing that can get lost after you take it off between dives to take your wetsuit off.
Mike