Hi Richard. My ST13 speedo is consistently 9% slow. If you ride the speed indicated on your speedo in Sydney traffic you'll be rammed from behind, from what I've seen of them. Even sitting on the limit is hazardous unless your's following a mobile phone user. They slow down to limit the accident damage, I've noticed.
Good choice to stay with Honda. There are other good bikes out there, but few as all-round great or as near-perfect as the STs.