Just to add another element into the mix for you to consider, is not just the weight/construction/durability of either camera, but the way they are put together (meaning, design, not actual construction) and whether that makes one or the other easier for you to use. As a quick example, hiking with a few photographers not too long ago, there were three Wista's on the trip, two metal fields (one being mine) and a woodie. At one point, as I was setting up a shot, the wood user was standing next to me and commented (almost in awe) at how easy my front tilt was to adjust, one thumb screw, tilt the standard with a thumb and forefinger, easy. I hadn't thought twice about it until he commented, then I saw him struggling with his front movements, two screws that had to be loosed at the same time, trying to flick the brass rails in while also holding the standard up to stop it falling all the way forward... a very cumbersome looking routine, and in the cold and drizzle, made me very thankful for the simpler handling of my, slightly heavier, metal field.
I just wanted to throw that in, because of all the wood vs metal debates I've read, they all seem to focus on the weight vs ruggedness debate, forgetting other practical considerations. So, just something to make your decision a little harder again!