I am choosing for a project between Pana HPX 500, Varicam 27FE and sony f900. The 500 and the 900 are 1080, the varicam is 720. DP is saying the varicam has the richest and nicest colors, but is 720p. I intend to show this in some theaters and festivales. Is te difference of 1080 and 720 noticeable in the big screen? is better to go in 1080 for some reason?
From my experience, the f-900 will be very slightly more detailed than the 720p Varicam.
But I like the Varicam camera better (though I wouldn't say it's colors are "richer").
I have just seen a movie I shot with the Varicam projected on a very large screen at a film festival on a DLP cinema projector. It was just fine for detail, and I sat pretty close to the screen! Not as detailed as a RED or Sony f-35, but as detailed as a typical film print at the multiplex.
If you do choose the Varicam, make sure to shoot in FilmRec mode and use the lowest "Dynamic Level" setting that will record your range of light. This is from my experience, others might have another approach. The choice is from 200% to 500%. The higher the setting, the more dynamic range you'll record, but if you don't need all that range, you'll need to up the contrast a lot in color correction. This might produce banding in the 8bit recording.
There is also a new menu setting in the VTR menu (it was a firmware upgrade) called "Compression Dark". Make sure you choose this setting or you'll have blocky shadows when recording to tape.