Closed Back Scoops provide additional support and control at the elbow. The allow for less forward/backwards movement. They are perfect for someone who likes the feeling of being locked in, in aero. They also do allow for a more relaxed grip on longer rides. Open Back Scoops allow for more forward/backward movement. They are great for cyclists who favor lateral movement. Open Back Scoops will allow you to make minor adjustments to your position throughout your ride while still providing more than enough control when in aero. The short answer: it's a matter of preference and both solutions will be a major upgrade to your existing scoops.