The darkness issue is that FCP automatically lowers the gamma so that the it will be correct when you view it on an external video monitor. The totally crappy and ridiculous part is that you can't turn this function off in FCP. It makes me angry every time I edit, since my footage never matches, for example, between FCP and After Effects, and I can't properly color correct unless I plug in a monitor. I often make video for the web that will never be seen on a TV screen, so it's really an obsolete way of looking at video on the part of Apple.
And they call this a pro app? Not from where I sit. We can only hope that FCP X fixes this stupid, stupid design flaw.