v8ka,
I've worn one or another ROC or ROO nearly daily for the last 5 years, so I suppose that provides a reasonable basis for comparison. Issues that you may want to consider include:
* Chronograph use: if you are among the few who use the chronograph function frequently, the ROO has the advantage, as it isn't necessary to unscrew the pusher covers
* Flexibility: While both can be worn with a wide range of clothes and in a wide range of social settings, the ROC has the advantage with long sleeves, cufflinks, or suits, and the ROO has the advantage with rolled up sleeves or short sleeves.
*Discretion: Neither will be recognized by non-watchies, but the size of the ROO brings it a tad more attention.
*Fit: Individual differences in wrist size and configuration may render one of them a better fit to you than the other. This might be the most important consideration, and it would be very useful to your decision making to have an opportunity to try on each.
You won't go wrong with either of them.
Park