You won't notice any difference in braking feel and performance from a caliper change, as there is little difference between the geometry of the brake mechanisms. Better brakes have better finish, and better hardware, but not much in the way if improved performance. Your best way to keep brake performance high is by regularly dressing your brake pads and keeping your rims clean. When doing a lot of riding, I go over my bike once a week for adjustments and maintenance. I clean and lube the chain, true the wheels, dress the brake pads with a file, and clean the rims with a rag wetted with acetone. If you keep your wheels trued, and the braking components clean, they work with less effort, and give you much better modulation. Where I live, there is usually at least one day of bad weather per week, and I use such days for bike maintenance.