I get this question a lot from my athletes that I coach. I have recently been reading about blueseventy's new wetsuit designs which are made for certain types of swimmers. If you legs sink in the water as mine do, you will want to buy Blue Seventy's Axis
If you are fortunate enough to have a more perfect body position in the water then you best bet is to choose the Blue Seventy Helix
These new suits aren't a bunch of hype or gimmicks either. They have been specifically designed to help facilitate a better body position in the water depending on your individual position.
I offer video taping to all my athletes who are able to meet up with me at my home training grounds in Arizona to help determine which body position they tend to have. Most of those who have swam competitively in the past naturally have a better body position in the water. Unless you are a natural swimmer the rest tend to be like me and drag their legs behind them which causes unnecessary drag and effort to swim at the same speed as one with a better body position in the water. The blueseventy axis is designed to have less buoyancy up front and more in the lower leg area which helps to lift your legs a bit more. However, if you are a natural swimmer with good body positioning in the water you will want the Helix which is more evenly constructed in terms of delivering buoyancy throughout the entire body.