What difference does it make if a rod is moderate fast or fast taper? I know that the rod bends farther down on a moderate fast taper, but that is it.

When using a slower action rod, more of the rod is in play when under load as you know. This results in a couple of differences between a fast and moderate fast, with all other things being equal. The MF rod will be more forgiving in that more of the rod is being used to keep pressure on the fish. This is good thing when fishing baits with treble hooks that generally are easier to pull loose during the fight. It is also a good thing when working tight to cover where fish are fought up close and personal, again allowing a little more  work to be done by the rod, and putting less stress on everything else-including you. Conversely, a F action will bring the power of the rod into effect faster, allowing faster hook-sets. This can be desirable when fishing a bait with a single hook-like a jig or soft plastic. In this case you want to be able to get the power of the rod into play immediately to drive home the hook. Once hooked these baits are less vulnerable to be pulled out, so speed is the key.

 

The above is generally accurate IMO. What I have learned is there are great differences how rods are rated in both power and action, and how a rod performs is a very subjective thing. Tight lines.

http://www.allfishingbuy.com/Fishing-Rods-Action.htm   Look at that site for a good visual of the difference. If you need more info ask away. 

Stiffness of tip. Mod is softer than Fast.

When using a slower action rod, more of the rod is in play when under load as you know. This results in a couple of differences between a fast and moderate fast, with all other things being equal. The MF rod will be more forgiving in that more of the rod is being used to keep pressure on the fish. This is good thing when fishing baits with treble hooks that generally are easier to pull loose during the fight. It is also a good thing when working tight to cover where fish are fought up close and personal, again allowing a little more  work to be done by the rod, and putting less stress on everything else-including you. Conversely, a F action will bring the power of the rod into effect faster, allowing faster hook-sets. This can be desirable when fishing a bait with a single hook-like a jig or soft plastic. In this case you want to be able to get the power of the rod into play immediately to drive home the hook. Once hooked these baits are less vulnerable to be pulled out, so speed is the key.

 

The above is generally accurate IMO. What I have learned is there are great differences how rods are rated in both power and action, and how a rod performs is a very subjective thing. Tight lines.

 

Very well said.

Keep in mind, the slower the rod the more it protects light line. For example, if you decided to go to lets say 2lb breaking strength a very fast rod would snap that on the hooksset. The slow rod would be more forgiving and when the fish surge you could protect that line better. Having a very fast action rod with light line is a recipe for disaster. This can be seen with flyfishermans love for bamboo. The reason is, its a very slow rod when your protecting a 6x-8x tippet.

Well I only have a moderate fast vendetta and was just wondering if it would be suitable for most types of fishing.

 

Stiffness of tip. Mod is softer than Fast.

Not necessarily. For Example a Steez rod has a very fast action yet very soft tip. A Mod-Fast Flipping stick is slower yet still quite stiff.

Taper doesn't have much to do with stiffness in any portion of the blank. It affects recovery, power, speed, and lifting strength. Stiffness of any portion of the blank can be related to taper, but is not a direct result of.