I use Flexcolor but can not help you answering your questions on how it differs from C1. Did you apply for a membership on the Flexframe group on yahoo? If not, you should.
I use both platforms, I find the user interface on PC a bit more clunky looking. Functionalitywise I have not found any difference. I use MacOS on the MBP and Windows on the studio machine.
Flexcolor starts as a fairly flat file. You can opt to process it like that and continue in PS or yo can make some starting adjustments in Flexcolor. I sometimes do one or the other depending on the file in front of me.
When working mostly in flexcolor.
I start putting the exposure at the level I like, crop, set levels, set curves, change color balance if necessary (or wanted), set a bit of sharpening (I always process in PS and do sharpening at the end depending on the medium I will be presenting the image on) and process into the file format of choice.
When doing most in PS.
I keep the file as flat as possible, set the exposure correctly and process into the file format of choice (tiff 16bit if I plan on wrecking the hell out of the file otherwise JPG).
There is also the option of converting FFF files towards DNG. This I do with packshots which afterwards are dropped onto a droplet or I have actions run over them via Adobe Bridge.
I hope this will help you on your way?
