dim, low-res screens which cannot be seen in normal daylight? Lenses which need to be tested and rejected before a good copy is found? Sensors with green stripes? Two batteries in one camera+back? Shooting rates like molasses? LCC files required for decent colour across the image? Incomplete lens lineups with missing leaf shutter lenses, tilt+shift lenses, you name it? Tolerance failures in tech cameras which make focusing impossible? Companies which promise openness and then go closed?
Carsten are you referring to Mamiya with the above?
Various.
Dim sensors, cannot be seen in daylight: all, to my knowledge.
Low-res sensors: all except perhaps high-end Leaf and Sinar E65.
Lenses which need to be tested to find a good copy: Mamiya, Phase.
Sensors with green stripes: Mamiya ZD.
Two batteries: all except Hasselblad, I believe.
Shooting rate slower than molasses: all.
LCC files: several, although here I am less sure. All tech cameras, almost certainly.
Incomplete lens lineups: almost all, in various ways. Rollei doesn't have a really wide lens for the Hy6, Mamiya has some iffy non-D lenses, Hasselblad has poor back support for the V system, leaving it without true wides, Mamiya/Phase don't have leaf shutter lenses, only Phase has a T/S lens, but it has corners softer than down pillows, and so on.
Tolerance problems with tech cameras, making it hard to focus: Silvestri.
Companies which promise openness, then go closed: Hasselblad H2->H3D.
Those were just as many issues as I could write down in two minutes without thinking too deeply. There are many, many, MANY more, such as insane prices, spotty support, dealers which blame problems for spotty cameras on the photographer, flaky Firewire connections and cables, dim focusing screens, inflexible viewfinder options, poorly thought-out firmware update systems, flaky software with brain-dead or out-of-date interfaces, and on and on and on and on and on and on.
This is almost ALL stuff which a D3x owner doesn't have to deal with. Some of the systems are better thought out than the rest, but there are still WAY too many issues and caveats. What is really needed is for a company to come in, take stock, and design a system which avoids all the BS and just works. Listening to Big Cooter and James Russell and others only reinforces this opinion. There is just way too much BS with MF systems at the moment.
And this is all just from what I have heard. I don't even own one yet. I have a Contax 645 system and two Blad Vs, and plan to get a Sinar back sometime soon, provided the whole Hy6 debacle works out reasonably. To my long list of problems, any busy pro could probably add another 100 issues. I have more than once just considered getting an A900 and a couple of good Zeiss lenses. Now I am watching the Leica S2 very carefully. Leica has a long history of top-notch products, and when they inevitably mess up, they stick around and try to fix things properly. I respect this company, and their lenses are awesome. If the S2 really hits the high-end studio fashion soft spot that Leica seems to be aiming for, it ought to really shake up the industry.