Here is my bottom line: If you want a quick, robust, boat for adventure racing or fast workouts, but don't want to spend $1M or be overly cautious with how you treat it, this is the perfect choice. I am 20% faster in this boat than my "performance" 'glass sea kayak.
Be prepared for a swim and some buyers remorse on the first few outings, but push through and it becomes fun. By the way, Cobra has stopped making the boat and no longer has any in the warehouse. You will need to buy a leftover in a shop or go used, but the build quality is quite nice.
To put things in perspective, I am able to maintain the Viper at an average speed of 5.7 mph over a 5 mile flat water course and that is more than a full mile per hour faster than I was able to achieve in my previous 17'ocean kayak. Granted, that took me 1 year to achieve with the first few months full of white knuckles and fear to even turn my head but this stallion is not too difficult to tame with some patience and practice.
The Viper is the perfect step between a fast ocean kayak and a composite racing kayak or ski because it is affordable and virtually indestructible while requiring the paddler to learn the essential balance skills needed for the skinnier boats and skis. The lack of primary stability forced me to learn proper technique yet the secondary stability was actually quite forgiving (once I learned where it was) as I climbed the learning curve. Now I find it nearly impossible to go slow in the boat.
How challenging is this primary stability you ask?
Let's put it this way. When you put the boat in the water it does not sit upright. It leans to one side or the other.
It has a fixed, fiberglass hung seat that I found was much better with a small block of minicell foam behind it to give the lower back a little support. I also added a little bit of pad bracing for the thighs so I can "lock in" when going through small rapids (I'd be scared to try Class III's or higher in this boat) yet allows my legs to be free with full movement on flat water.
The narrow hull just in front of the cockpit allows for proper paddle action (especially with a wing paddle) so you can start close to the boat and get full rotation while keeping the blade at the proper angle throughout the stroke. If the previous sentence did not make sense to you then the boat probably is not for you.
The Viper is an absolutely wonderful boat for an experienced kayaker who has a 'need for speed' and is ready to take it to the next level without risking a ton of money for a true Olympic K1 or composite race kayak before they know if they’re going to stick with it and master the long, skinny boats.
Yes, it is very tippy. No, it is not a boat that you are going to lean back and gaze at the stars in without getting very wet. No, you won't cry if you scrape a few rocks with it because it is plastic. No, it is not for the average recreational kayaker with poor balance and paddling technique. Yes, it will deeply reward those who master the balance required to unlock its full potential.
I will give this boat a rating of 8 since the comfort is not there, but I guess a fast tippy boat does not need the comfort if you are passing everyone on the river, of course as long as you can keep it from dumping you.