One of the major arguments that people are bandying back and forth is the lack of video and LiveView for the α850. When you consider than antishake in the full frame is still a unique quality (only the SONY has it), LiveView and Movie mode seem rather silly.
There are plenty of SONY "LiveView" cameras to pick from (four at last count, all under $1000)
and the level of movie magic is still not anywhere near perfected. I will not miss those aspects from my still camera and if I wanted them, I know right where to go.
So, detractors need to get over themselves. You buy a camera for a purpose. My choice was to expand the results I am getting from my two-year old α750 and get into Full Frame, w/o having to mortgage the house! The α850 handed me that with a $700 discount against the A900. Having already been conditioned to a 98% Viewfinder with the α700, the α850 really is no big deal. I rarely shoot at 5 fps, for the most part (usually experimentally, not as a routine practice). Again, this is a minor consideration for the same luxurious 24.6MP image.
I can say with some assurance that the α850 is directed right at the serious APS-C Hobbyist (people who realize quality optics cost a bit and dont shirk at $1000 price tags for some equipment)
and it frees us with a choice to move up to making a better image, w/o entirely breaking the bank. I know for myself, it appears to be what the doctor ordered. Its just a shame we could not have had it a year ago, eh? Back when our money used to be worth something.
I do not want to create any tension in regards to class warfare among the various models
but, there simply are degrees that people will not exceed in their hobby pursuits. This is often determined by forces outside the hobby
and I think you (full well) know who I mean. Just accept that there are boundaries that are gingerly or not crossed
or pity the fool who does.
Love of the craft
may it always be ... ours.
- BFA, Digital Photography
A Photographer Is Forever
Look, I did not create the optical laws of the Universe ... I simply learned to deal with them.
Remember: It is usually the GLASS, not the camera (except for moving to Full Frame), that gives you the most improvement in your photography.