In theory they work in a different way But i think that behind all this theories they work in a similar way
Seems like the debate between the two systems is going to go on till mountains become canyons and the canyons become oceans.
It is very hard to explain the differences until you actually try them both out. People have an ingrained idea about how insulation and waterproofing work and most people cannot seem to let go of the idea of materials being hydrophilic and hydrophobic. But the two systems are very different.
The pertex pile system works on the idea of quickly evaporating liquid spread over a wide surface area, it works on the heat from the body. When the outer fabric, the water resistant pertex, is overwhelmed, the system continues to work much the same as a wet suit, staying warm enough that the cold of moisture doesn't threaten the wearer. If there is no heat the system cannot work. And when the pile is too thin, such as a Marmot Dri-clime jacket is used in sub-zero temperatures and the outer shell is overwhelmed, the wearer will get very chilled while being wet. All pertex/ pile systems are not supposed to be washed in waterproofing solutions such as Nikwax TX.Direct, because the pile clumps up and loses its ability to spread out the moisture from the skin.
The Paramo Analogy system doesn't depend on heat to work (though heat helps to dry out the system, of course). As Chris Townsend explained earlier, it is the physical configuration of the outward facing fibers (pile fibers face inward) of the pump liner, the "V" shape that Chris mentions, or, as I read it, the denser base of the fibers that grow progressively more open the further they extend from the base of the pump liner, that actively "pulls" moisture from the inner surface of the liner to the outer. No heat is needed for this. It's a physical attribute of water that causes it to react with the shape of the liner fibers in this way. You can pour water onto the inner surface of the liner and watch it, not spread out like with the pile in the pertex/pile system, but get sucked right through. Using waterproofing in the Paramo system does not affect the liner and helps to make the thin polyester shell water resistant enough to keep moisture running off the surface of the whole system. But it is not strictly waterproof in the same way as Gore-tex or eVent. If you wear a pair of Paramo Nikwax Analogy Cascada pants... their "waterproof" pants... and sit down in a puddle, the pressure from your backside will press water through the outer fabric and you will feel wet. However, when you stand up the moisture will quickly be drawn away from inside and you will dry off quickly. The Paramo system doesn't rely on impermeability to keep you dry, as Gore-tex or eVent do, but on active movement of moisture. This is the important difference with Paramo. It's why you can rip the fabric, patch it in the field, and there will be no reduction in performance. It's also why, if the washed-in weather proofing wears out the whole system still keeps you dry even if the outer shell is completely wetted out. It is also this openness of the fabric which helps to make the Paramo system extremely breathable. And unlike the pertex/ pile system if you are immersed in cold water the Paramo system will not keep you warm like a wet suit. A thicker pertex/pile system, like the Buffalo Mountain Shirt or Montane Extreme Jacket, are all you need in cold winter conditions... not even a base layer (pertex/ pile works best directly on the skin, for Paramo it doesn't matter) is needed to stay dry and warm. The pertex/ pile system was designed to take the place of the traditional, base/mid layer/shell layering system (and is based upon Inuit polar clothing design). The theory is that it is okay to get wet as long as the body doesn't lose precious heat. Just like a wet-suit. Many people in the very wet and cold British conditions swear by pertex/pile. For those for whom being dry is more important, and for whom the pertex/pile system is much too warm, the Paramo system is the rainwear of choice.
Many people prefer to use the Paramo system only in winter because the pump liner is still too warm for them, too. Personally whenever it rains hard enough in alpine regions here in Japan the rain is cold enough to warrant the Paramo. I have only ever used my Montane Extreme Smock and Epic Jacket (thinner pile, no longer made) in dead of winter. Otherwise it is much too hot.
Paramo is heavy. If going ultralight is paramount, then this system will not work for you. But since I use the Paramo jacket as a waterproof shirt I can wear it almost all the time, except when it is hot, so I use it in lieu of midlayer shirt.
Pertex/ pile is very bulky. Too much so for most practical use when not being worn, and since I get too hot using it most of the time and cannot stash it away easily, I almost never use it.