I had an ST4 for 2 years/20k miles, first gen 916 motor. It's more like the FJR than it is different.... except more leaned forward, more wind with fewer options for aftermarket windscreens. Power and performance is similar in that they both have more power and torque than most people need or use. You might say what the FJR is to the ST1300, the ST4 is to the FJR, another step toward the sport end of the spectrum. With the sargent seat I could do a 300 mile day comfortably, but the wind noise bothered me. It's a bit lighter and thinner. If you rack up the miles than the 6k valve adj interval is expensive unless you have the skills to do it yourself. The original owner of my bike had some problems and spent some serious money fixing them, I had almost none in 20k miles. The guy I sold it to rode it a bit, then had some engine trouble and ended up parting it out at about 45k miles. Bummer for them.
the only other thing I'll add is that it is a Ducati, and there are few other bikes - imho, shared by others of course - that have the soul of a Duc. There's just something about the sound, and the feeling you get from that torquey vtwin that sets them apart.
