I have a Zi. Its a nice camera that has its quirks, like a lot of cameras.
The lens is spectacular. It rivals my mamiya 6 50mm lens based on the few tests I have done. But it's slow. I predominately use it on the wide end , which is a little faster, but it still means I have to be careful with what film I use in it.
as mentioned above, the LCD is a disaster waiting to happen. Luckily mine still works fine, but if I open the rear door to much when loading film, it sometimes blinks in and out. so I am very careful when loading film. based on years of using the camera, if the LCD goes, it is almost useless. I would more than likely only use 1 film in it as you need the LCD to change ISO and my wheel is starting to get click errors, it jumps all over the place so counting clicks will not work. so I will dial in my ISO along with any filter factor and stick to TMAX 400, with filter and ISO of 80 ( I shoot it at 200) and call it a 1 film camera.
the results from prints, both scans and wet prints are great. it is a little large for the size of the neg, also an odd shape. it does fit in my cargo pants and shorts, so for many years it was one of my hiking cameras. like any auto focus range finder, you need to pay attention to the distance meter in the viewfinder to make sure you are in the ballpark of what you are focusing on. like mentioned above, the meter works very well. I get perfect exposures when using velvia. I add a little for B&W neg film as it, like most modern meters, underexposes neg film, more than likely to save highlights in slide film. once you use it, you adjust accordingly.
the tiny flash actually does come in handy. it has saved a few shots because of the slow lens.
all in all its a great camera. but if I could find someone who was willing to trade even for a fixed lens fuji 645 with a wide lens, I would take it. I have more faith that it will last longer. I dont use the camera as much as I used to, maybe 5 rolls a year. if the LCD was not a factor, this woul be one of the best travel cameras for me and the way I shoot. if its the right price I would tell you to consider it. but paying a premium for it over the fixed lens cameras is not worth it in my mind. I'm sure others will disagree, but that's just my opinion.. if you buy one, make sure you can return it for free after using it. to many people never mention the LCD when selling.
john