But to be honest I also bought a simple Kalt 58mm metal shade, and a couple of 58mm filters, which I prefer instead due to the shade's deeper profile over the lens. (And the fact that folders are supposed to have round, not square, shades, right?)
When using the camera I tend to just carry it around open. I mount it to a simple L-bracket with a cable release in the trigger position on the bracket. This keeps my dirty/sweaty paws off of the body and works well for me.
Another idiosyncrasy is, of course, that it's a bellows camera designed to be handheld. But if you have prior experience with any format bellows camera—especially any older medium format folders—this is not really a big issue. You'll already be conditioned to keep your hands away from the soft folds. For others, however, this might present an issue.
Yet another thing to get used to is the meter output display in the viewfinder. It's discreet, not continuous. In other words, it displays only whole shutter speeds. No fractional speeds. In aperture-priority auto mode this is not an issue. But in full manual mode it's a bit disconcerting to be unable to get accurate feedback for intentionally set in-between f/stops.
Oh, and the aperture ring click stops are set at half-stops only, instead of the more usual third-stops. And the auto exposure mode requires you to set the aperture ring to only these half-stop detents in order to work. Or so the manual states. These issues may or may not be important to you.
As far as the design flaw goes, it's something I haven't heard mentioned in any review of this camera. I noticed it at our local state fair last August when pointing the camera skyward at one of the rides. It's that the viscosity of the grease used to lubricate the focusing mechanism is too thin. At least on my sample.
If I point the camera up severely, or swing it downward as I walk, the lens moves slightly from the previous focus setting. When I pointed it up at the ride, I was attempting to prefocus on a known spot, then wait for the action to enter the frame. But while watching the rangefinder rectangle as I waited I noticed the focus shifting appreciably. I ended up having to keep my fingers on the collar to keep it in position.
I still got the pictures. But it was annoying, since a lot of non-autofocus camera work requires prefocusing, and trusting that focus to be maintained if you lower the camera momentarily from your eyes. I'm assuming this issue could be relatively easily fixed during servicing. But I couldn't guess at the cost.
But even with these issues, I wouldn't sell or trade away this camera for anything. The lens is killer sharp, if that's your thing. And no GF670 review would be complete without mentioning that shutter. It is impossibly quiet. I mean, my ear is only a few inches away and, if I'm outdoors with normal background noise, I simply cannot hear it. You have to try one of these yourself to understand. It's eerie.