OK firstly the theory behind a wet suit is to make you faster by making you more buoyant in the water, and by reducing the drag on your body.
The maximum wet suit thickness that is legal under ITU rules is 5mm. However most suits are not 5mm all over.

The zoot suit has 5mm pannels built in to help the buoyancy (giving that motor cross look) but also has the thnner neoprene around the 5mm chest pannels and the arms to help keep the suit flexable. The main difference is that other suits do the same thing except they have a uniform taperof material over the suit(non motorcross) between the different thicknesses and thiner pannels around the arms so the suit is flexable.

Other brands to look at would be the Blue Seventy or 2XU, both make great suits particularly 2XU who are also great value. The best thing to do is try on a few different brands because they are all cut differently and so they all fit differently. Personally i dont like Orca as i feel they are cheaply cut and dont last a long time.

Some of you may or may not know, i work in a tri-store in austrlia and we sell a huge rannge of products so if any one has a specific questions then i might be able to help.

I've been using a Xterra Vortex full for 3+ years and despite teh poor review under reviews have had no such issues. Very durable and the only time I dealt with customer service was when ordering it. They are only sold online or over the phone so give yourself the time to allow for the delivery to avoid any close calls.

I have a Nineteen Pipeline and I absolutely love it! I rented a Zoot right before and I find the Nineteen much easier to get on and off.