[monkeyhatfork]

different fins creat different workouts I rotate between mono and bi-fins and also short swim training fins as well as no-fins, another added bonus is that mixing things up keeps it from feeling monotonous if your in the pool several days a week. The mono could also possibly allow you to see greater distances which in tern would make said distance seem more comfortable to try out with the bi-fins. Here's the thing, depends a great deal on the gear, a high end bi-fin will outperform a low end mono and vise versa. It's essentailly up to you. If your in this for the long haul I'd take the (different tools for different jobs)approach, eventually most people end up with a closet full of different fins that they pick and choose from to suit the situation. Each has an advantage. I got bi-fins for video, u/w hockey, and certain shore dives, otherwise I use the mono, personally it just seems a more natural,comfortable and efficient movement, but thier are situations when they can be impractical and thats when the bi-fins go on.you don't always need to stay in an arms forward position with mono check out the Herbert Nitsch Cave Diving vid on youtube example of a relaxed looking dive while holding gear