Viper was the first job I reached level 100 on. Enjoyed it. Didn't see what the issue was. The job gauge with the double-blade is confusing and I cannot glean any information from it but that's okay, I could still play the job just fine. Wound up going back to Samurai since I prefer how my outfit looks there, not because of anything wrong with Viper's gameplay (Viper has cooler animations when in awakened mode).