i was thinking about buying one also, and rode it last week. After coming off a k75 the 1200rs did feel very heavy in steering the front end, especially at slow speeds in stop and go traffic, not sure if it was low tire pressure or just the nature of the beast.
On the highway it pulls strongly, has a smoother shifter and definitely a sport bike seating position with weight and hands on the drops. There is no throttle drag screw like the k75, so for long distance there would be no rest for the right hand. It did feel heavy to me even though it has lots of power. i was hoping it would be a bigger, more powerful sport touring version of the k75, but it felt more like a big heavy sport or race bike to me. i have a ducati for track days and sport bike riding, so the didn't fit my needs. If i could only have one bike then the 1200RS might be a good choice but it is more sporty than touring to me. The k75 does everything well and is hard to match for overall riding.
i would be interested to hear your comparison also.