Originally posted by Adam The K-3 II is in the flagship class, which means you get a full metal body, unlike the K-70. The former also has a more durable shutter.
That said, there may be something new just around the corner. If your budget is that high, I'd wait a bit.
I'm not normally one to recommend waiting, but in this instance I'd have to agree. We're starting to see the first rumours (albeit unsubstantiated) that the K-3II is about to be replaced, and the timing is right. There should be attractive discounts on the K-3II coming fairly soon, or you might decide that the improvements offered by the new model are too tempting to ignore.
The K-70 has had great reviews so far, and I've seen no reports of design faults, so that's definitely an option too, but the K-3II or whatever replaces it as the flagship APS-C model are heavier-duty cameras with a more robust build.