I can never resist this discussion when it comes up, as I seem to have had a run of bad luck with discs, both cable and hydraulic, which means I would only ever grudgingly put up with them on a mountain bike where I *need* the extra power/lack of effort at the lever etc.
Based on my experiences, putting discs on a roadie is just a good way of making it heavier, more expensive, noisier (my biggest bug bear, deafening squeeling in the wet) and potentially draggier, since disc brakes seem to go in and out of alignment and discs seem to warp far more frequently than calliper brakes and rims.
For now I’ll just suck up the cost of some decent callipers and fancy Swisstop pads and enjoy silent, drag free braking, albeit perhaps having to anticipate slightly longer stopping distances in the wet!