I enjoy snowboarding, and have the same dilemma: finding something which is waterproof and still breathes.
For a long time I just made due with Goretex and just took care to open vents when I started anything aerobic. It wasn't ideal at all. Softshells are nice, and they definitely breathe better, but in a rainstorm you're still going to get wet.
The real problem with Goretex is the expanded PTFE membrane (with the micropores) works just fine, but they've needed to add a layer of polyurethane to protect the membrane from dirt and oil. So to pass moisture first the PU layer needs to get wet, then it can pass it's moisture through the PTFE membrane. This drastically slows down the rate at which it can breathe.
Last year I found the solution: eVent. It's an expanded PTFE membrane like Goretex, so it's just as waterproof as Goretex, but they've found a way to protect the membrane without the PU layer like Goretex has. The end result is it breathes
a lot better. In my experience, it breathes about the same as a thick fleece.
Goretex marketing has some nice demonstrations which they say shows Goretex breathes as well as eVent, however, all the demonstrations use high humidity and high temperature (think when it's already a sauna inside your shell), which is where Goretex works best. The problem is at low humidity and temperature, Goretex doesn't really work, while eVent works about the same regardless.
Wearing REI's eVent pants and jacket, while skinning I was able to keep everything zipped up on everything but the steepest ascents and wasn't damp at all. On the steepest section unzipping my jacket halfway did the trick.
So, if you want a shell which is truly waterproof and breathable, eVent is by far the best choice going. REI has a nice one for $240:
Showers Pass Elite 2.0 eVent Bike Jacket - Men's - Free Shipping at REI.com
Summed up quite well:
The basic issue with Gore-Tex for most people is that it is a "wet" membrane. That is, the interior of the membrane is sprayed with a very thin layer of polyurethane, which is a hygroscopic fabric, in order to protect the pores of Gore-Tex from being clogged by your body oils, dirt, etc. The humidity within the garment rises until condensation occurs upon this polyurethane due to the cooler outside temperature, at which point the PU absorbs the moisture and then since the membrane is also at a higher temperature than outdoors, it can evaporate through the Gore-Tex pores. What this means is that the interior of the garment is always going to be at a high humidity level, which makes most people feel damp and clammy once they start sweating no matter the efficiency of this process.
The only difference between the various "types" of Gore-Tex is the thickness of this PU layer applied to the membrane. Over the years Gore has managed to reduce the thickness of this layer significantly for its more "technical" fabrics, thereby increasing its ability to carry water vapor across the PU barrier. Its basic mechanism of operation, however -- condensation, absorption, evaporation on the other side -- has not changed.
eVent changes this paradigm entirely. eVent actually *vents* -- water vapor never condenses anywhere inside the garment. There is no polyurethane "wet layer" to cause humidity inside the garment to rise, and the result is that most people *feel* dryer even under conditions that would have them feeling miserable with Gore-Tex. As a result, like the others here, I feel much dryer in my eVent jacket than in a jacket with a PU "wet process" membrane such as Gore-Tex, because the interior humidity of the jacket is so much lower -- Gore-Tex doesn't move water vapor across the PU barrier until the humidity reaches condensation point at the barrier, while eVent starts moving water vapor immediately and the humidity never reaches condensation point.
So maybe Gore-Tex with a very fine/thin PU layer *can* move as much water vapor as eVent -- but only under conditions of high interior humidity that most people interpret as "damp and humid". That's just the nature of a "wet membrane" process such as used by Gore, regardless of which Gore-Tex fabric you get.
NOTE: I'm not employed or sponsored by REI or eVent. It's just a product I personally bought and use.