What Type of PVC are people using for their racks

Ok im looking at starting to build PVC racks and Im curious what type of PVC people are commonly using. Theres three types out from the suppliers Ive talked to, and will I'm about 100% which type I need Id like to hear some feed back.

Expanded PVC- comes in lots of colors, very light, normally used for signage and displays.

Type1 PVC- normally comes in grey, hard core, more like PVC pipe then they expanded stuff, heavier

Type 2 PVC- also comes in grey or white. hard core and extremely hard surface, made to withstand surface impacts

Im guessing most of the racks and caging out there are made form Expanded PVC and chemical welded, from the manufacturers ive looked at. I know there are some that use thicker material and screws to hold together.

Im looking at a couple processes that will set my racks apart from the rest, and I would like to hear your opinions on the materials used in yours.

Most use Expanded PVC or EPVC. ABS and HDPE are also great plastics.

No More opinions? What about High Impact Polystyrene? has anyone worked with this?