i recommend paddles and a pull buoy. during the main part of the build and racing season, i do about 25% to 15 % of my total yardage with them. but it is
essential that you use the right ones--some paddles are worse than useless. i don't have any connection to the company that sells or makes these, but this is what i suggest:
http://mplx.com/hans/original.html or, if you are very big, very strong, or an advanced swimmer, then these:
http://mplx.com/hans/gripper.html what's better about these paddles? well, they have holes, which helps smooth the water flow, improves feel of the water a bit, and reduces the load of the paddle (and the load on your shoulders). and they are simple and cheap. but
most important: they don't have any tubing around your wrist (which 95% of paddles do) and they are designed to be used this way.
why is that important? well, you have to try it to understand. if your stroke is flawed a lot or slightly, having paddles strapped to your hand will do almost
nothing to correct those flaws. on the other hand, if you use these paddles, many of your stroke flaws will cause the paddle to "peel off" your hands and wrists, which will force you to correct those flaws by teaching you to swim in a way that keeps the paddles pressed to your palms. that's the simple explanation. and this advice comes from me, who used to be a back-of-the-pack swimmer and is now a off-the-front-of-the-pack swimmer. and i have coached others to have similiar huge improvements in the water. so i ain't making this up.
Where would you want to swim ?