I'm a wildlife cameraman and so I need long lenses and high fps a lot, so the 2k mode will probably do me a lot of favours. But for times when I don't need extra lens magnification or fps above 30 (so landscapes, flowers, sync sound pieces etc.), I'm thinking that shooting 4k makes sense for a couple of reason; firstly of course 'cos it's better, higher res, secondly if you've got it 4k in your archive you've potentially got more future clients for it, and thirdly that you can get a wider angle of view from your lenses (ie a 17mm lens will be pretty wide on 4k, but windowed 2k it'll be about standard lens fov). Does this mixed shooting make sense, and presumably in post mixing the two won't be a problem?
Steve