HDPE vs PVC Schedule 80

OK so here is a summary of my investigation. I reached out to both manufacturers, the PVC - Schedule 80 that was already approved and the HDPE conduit that has been submitted. This is what I found:

PVC Schedule 80 Manufacturer: "We don't know too much about HDPE, we don't really see them as a direct competitor. We focus most of our literature on how PVC is better, lighter, quicker to install than metallic conduit."

HDPE Manufactuer: " HDPE is a superior product to PVC. A lot of people are updating their specifications and moving toward HDPE.

HDPE comes in continuous lengths. Less couplings and gluing. If you do need to couple there are special two part epoxies that need to be used to glue special HDPE couplings. There are also HDPE Shurlock couplings which are UL listed and can transition to just about any other conduit system. HDPE when laid in a trench is flexible enough to get around most obstacles. The one thing that is worse about HDPE is that it does have more of an expansion contraction issue than PVC. Though it being underground that should not be as much of an issue. HDPE can be installed at -40Def F while PVC gets very brittle at a little below freezing. Wall thickness is similar between PVC and HDPE and you can see how they compare, you can get a Schedule 80 HDPE conduit and that will actually be slightly thicker than the PVC schedule 80 conduit. Not all HDPE is UL listed though, only Schedule 40, Schedule 80, and SDR 13.5 HDPE can be UL listed. If you don't ask for it you will not get the UL listed one."

Since HDPE can only be installed underground, I don't see it having a worse contracts expansion properties much of an issue. It seems like there are some serious cost benefits to using HDPE duct and as it starts to get more accepted it will surpass PVC at least for all underground installations.