The HP's canopy is uncoated, but the fly is coated. There are extra vents in the fly that the standard Hubba Hubba doesn't have. I think users will notice a slight difference in breathability over the mesh canopy (where the mesh is more breathable), but the HP version will be warmer due to it's wind blocking capabilities.

The new material of the HP is a step up from the standard Silicon coated nylon of the standard version. For those who already have the standard, I doubt an upgrade would be warranted, unless you love the livability and weight, but need more weather resistance and durability. For those who don't currently own a Hubba Hubba, the HP version is worth checking out. My personal opinion is that it is one of the best freestanding sub-4lb two man tents on the market for livability, durability, weatherproofness, and ease of set up. Both the Hubba HP and the Hubba Hubba HP are in a category by themselves.

The best way I can think of how to categorize them is by a comparison of hardshells. The standard Hubba Hubba would be a Marmot Oracle Jacket whereas the Hubba Hubba HP would be a Westcomb Specter LT. The Marmot is an excellent jacket, but the Westcomb uses better, more advanced materials and superior construction resulting in better performance. For those who believe the Oracle will suit their needs and budget, then this is an easy choice. However, for those who won't compromise quality and want the best performance and fit (and are willing to pay for it), the Specter is the one.