I have a 4k - it's an OK camera, especially if you're just using a 50mm lens on it and can therefore use the built-in vf/rf.
My only complaint (and this might just be my sample) is that the slow speeds are tempermental - you have to wind slowly and all the way to the end, and when you want to take the shot depress the shutter button very evenly and all the way down, or else the slow speed mechanism doesn't engage. I've had it in to my local repair guy - he's overhauled it and says that's as good as it gets. Fortunately, I don't use the slow speeds that often
I'm tempted to get another one to see if this is a systemic problem with these cameras or not - but then, I really don't need another 35mm camera