I have recently purchased both. The Helix is a closer, yet still comfortable fit, whereas the Dri-Release is cut slightly fuller. Both are soft to your skin, but the Dri-Release is slightly warmer, very soft and comfortable. I use the Helix as undershirts with dress shirts, but both serve as attractive outer garments or as sleeping shirts. A limited choice of colors are available. Go for both to cover a greater temperature range.