I'm 5'11" and ride the 52cm Secteur, but I have dumpy little legs so needed to go small for the stand-over height.
IMO, on-line calculators and bike-fit advice almost always misses the central issue when considering which size bike to get.
The fit of the bike depends to a large extent on what you are doing with it. For instance, I
should ride a medium or small MTB to give the best off road control. But, I choose a large frame because I tend to treat it as more of a day-long multi-surface bike (60 miles on a canal path) rather than something that I can throw at extreme off roadery. It will do the off road stuff but it's a bit less controlled when doing so.
Similarly, a larger frame on a road bike will (up to a point) be better for day-long comfort as you've got more room, it'll be more stable with a longer wheel-base, which also means it won't be as upset by road surface imperfections and the compact frame of the Secteur allows more stand-over room. Conversely, it won't be as responsive as a shorter wheelbase, it'll obviously be heavier, it might not be as good at climbing and you probably won't be using your core muscles as much as if you were in a more hunched position.
Basically, if you want comfort, go for a larger frame, if you want speed and power, go smaller.
That said, want to swap for a Secteur Sport? Also 2010, done about 850 miles, with a 52cm frame?
I would have it myself if I didnt already have one.
