I'm trying to choose between Gore-Tex Pro and Conduit - any suggestions? I tend to sweat like crazy and breathability matters to me a lot. I usually go with a soft-shell for this reason, but am starting to do some things where a hardshell is needed.

Durability matters, too ...

Both Gore Pro Shell and Conduit (Terrashell) are going to have very similar breathability... near the 40,000 MVTR (moisture vapor transfer rate) level as a matter of fact. I am not sure of the MVTR of eVent but I have heard it is somewhere between the levels of ProShell and Windstopper due to it's deconstructed nature. Keep in mind also that breathability is very much a function of the thickness of fabrics meaning that heavier weight fabrics are not going to be as breathable as lighterweight (thinner) fabrics. So, typically lighterweight = more breathable/less durable. Heavier weight fabrics = more durable/less breathable. To get the best balance of breathability and durabililty... I would go ProShell at this point. Check out the Argon Jacket or Beryllium Jacket from Mountain Hardwear for beautiful examples of well executed ProShell jackets. Hope this helps!

I second the suggestion that you consider an eVent jacket. The only eVent jacket I have experience with is the Rab Latok Alpine, which appears to be durable although I haven't used it extensively yet. However, Westcomb makes some eVent jackets that have gotten good reviews and I understand that they are made using a ripstop fabric which should be very durable. The other option that you might consider is something along the lines of the Cloudveil Koven Plus Jacket which is made with the Schoeller c_change fabric. The Schoeller c_change membrane is really impressive, and I've been using this jacket for skiing without any problems so far this season. The c_change material seems to me to be about as breathable as the eVent fabric, and more breathable than Gore-Tex Pro Shell.

With your parameters set Conduit is your answer. Sweating like crazy= sure fire over-heating. If you need a hard-shell but won’t be in downpours you may want to look at a hooded wind shirt(GoLite Ether, Patagonia Houdini) but since you want durable I'd say steer clear of wind shirts and go conduit. The durability between gore-tex and conduit is negligible.

Check out some of Patagonia's 2 layer stuff. In my experience, Conduit has been only waterproof to a point. Think skiing in the Pacific North West wet snow on a chair lift and wet thighs. The Gore-Tex is certainly gonna keep some of the sweat in though. IMHO, Patagonia does a good job of being waterproof, breathable and durable. Another option is something with eVent in it - like the Stoic or other - but I think those tend to be thinner (and lighter) but less durable. Good luck and I hope this helped!