To make I better choice when buying a new rod there are a few things you should know. When choosing a rod there are 3 main factors that will determine how the rod will perform in actual use.
  Action refers to where or how much of the rod will bend. With equal weight a fast action rod will start to bend more toward the tip where as a slow action rod would tend to bend over the entire length of the shaft. A medium action rod would start to bend in the middle. The action is controlled by the taper of the rod itself. A fast or short taper would make a slower action rod and a slow or long taper would make for a faster action rod.
  Power or strength is the amount of force needed to bend the rod. The thickness and type of rod material will determine this. A lot of rod manufactures and anglers get this confused with action. Most rods when marked light-action are referring to power not action. The best way to tell the power of a rod is to check the line weight ratings.
  Sensitivity is the ability to transmit vibrations from the line through the rod and to your hand. By taping lightly on the tip with your finger you should easily feel the vibrations holding the handle of a sensitive rod.
  The thickness and density of the rod material will make a deference. graphite is more sensitive than fiberglass and boron is denser and more sensitive than graphite. The ferrules also make a difference, metal ferrules are far less sensitive than graphite. A one piece rod of course would be the most sensitive. The rod blank should also continue through the lenght of the grip. Single foot guides add less weight and help retain sensitivity verses a double foot guide which is heavier and must also be wrapped in two locations. Also the rod action plays a major role, fast action rods will be more sensitive than a slow action rod of the same material. Don't confuse a lighter more flexible rod with being more sensitive.