Different fins for differnt purposes. A solid stiff fin or a turtle paddle fin is what you should use when diving in currents.
that is one of the least educated things I have read on here. I really would expect that someone certified as a "divecon" would be smarter than that.
yes, certain styles of fins work or fail to work best for specific things, stiff fins like turtles are quite good for tight space work were everything except speed is required, they suck in straight line speed and endurance that is required to overcome a stiff current. It has been shown time and time again, that moderately flexible fins are faster and better for endurance that stiff blades.
speed- yes there are the rare times that speed is important, overcoming a current is a poor excuse for needing speed as you should plan your dive and dive your plan. planning a dive that you have to overcome a current is poor planning.
But... I don't care what fins your wearing, if you don't have proper technique, proper conditioning, and match the fin to your style and fitness then you are wasting your money.
this means that you must try fins, lots of them, Fitting a fin is not as simple as "I wear a size 9", the fin must of course fit your foot, but that is only one of the criteria to finding the right fin for you. Some fins are great with a slow powerful kick, some with a high cadence lower power kick, some are better for a back kick or helicopter turn, some frog kick, some can actually scull. You must fin which fin works best with your personal set of skills, no testing or other opinions can make that decision for you, sure some people can tell you what they like or dislike about a fin, but then there are the "others" that appear to be helping you, but really have never actually tested all options and determined the good and the bad