Thanks for asking.
The difference is the material!
First off we are upgrading the Polartec PowerStretch (300) for the new Polartec PowerStretch Pro (300). Advances in the material from Polartec have improved the material. Both have a 2-way body-hugging stretch and is very breathable. Some call it all-way stretch. (For range of motion and least amount of bulk this is the best undergarment on the market.) With the Pro, it also offers a "hard shell" outer layer for durability as well as a more modern design. Hey, you've got to look good, too, right?
You can find more about Polartec PowerStrech Pro at
Polartec® : Overview
The ActionWear 300 Jumpsuit is made from polyester fleece with has a 1-way stretch. This material costs 1/4 of what PowerStretch costs. This is actually being discontinued.
To give you another option, we have our ActionwWear Professional. This is also made out of a 1-way stretch material but it has an hard outer-shell, too. It's not nearly as stretchy and form fitting as the Polartec PowerStretch Pro, but the users of this garment love the fact that it is two piece. You can use the pullover for other outdoor activities, too. With a two piece garment you will have additional material which creates some bulk around the waist and hips. It is designed with the thought that the diver can wear this on their way to the dive site.
They are both rated for the same water temperatures.
If you can get to a DUI DOG Rally & Demo Tour event, you can try both of them out yourself!