Had an opportunity to do a relatively long TR involving both highway and city riding. Before I write down any details, I can say that people who do TR of the RS will either fall in mad love or completely get surprised by what this little machine can do. I think most of the details are already captured by some of the posts in this thread, but still I like to share my own experience.
Seat height - Slightly on the higher side compared to S. Initially I thought that it would be uncomfortable even to do tip toeing, but that wasn't the case while doing the TR. For my height, it was very much comfortable and felt at home.
Engine smoothness - I was completely taken back by how smooth the engine was. I felt as though one could coast or cruise in the first gear itself and that was the level of refinement the engine offered. Of course, I felt minor vibes at the handle bar when I crossed 8000 RPM in the 2nd/3rd gear. It was only after the Test Ride I came to know that the bike was still under running-in period (around 300 kms on the odo).
Engine performance in the low/midrange end - Low end torque is good for a bike like RS. I could do 50 kmph in 6th gear without lugging. From 50 to 80 kmph in-gear acceleration (in 6th gear) is as good as my Ninja 650 or even better than that. After 80 kmph, it pulls brilliantly. In terms of engine RPM, 3000 to 4000 RPM has good torque even for the the 6th gear. From 4000 RPM to 6000 RPM, it pulls hard (but not madly). It is after 6000 RPM, it slowly starts showing what the bike is. Forget about touching 8000 RPM in the 6th gear as one will not have road to deal with the deadly combination of high speed (around 160 kmph) and brutal acceleration. At least I neither have the skill nor the courage to take the bike beyond 8000 RPM. This is all happening in the 6th gear. So one can imagine what the acceleration (above 8000 RPM) will be in lower gears. Of course I tried to do that in 3rd gear for a brief moment, but it was a nightmare for me to deal with the beast of an acceleration. It must be noted that the TR was done with the riding mode set to street mode.
I will leave it to others to say some thing about its top end performance.
Suspension - Many have concerns about the suspension stiffness, but I had no issues for my weight. I weigh around 100 kgs and the suspension was apt for my weight. It was neither stiff nor soft for my weight and so I was comfortable on the bike. All the road undulations did not unsettle the bike. On a couple of bridges that I crossed, there were big undulations and the bike glided over them without getting unsettled. I think my weight was the main factor for the suspension not to be so stiff. My friend (weighing around 80 kgs) rode the RS in the return leg and found the suspension to be stiff.
In the past, I had ridden the S model and felt it to be more softer.
I can safely conclude that the default suspension setting is best suited for spirited riding on smooth roads for the riders who weigh between 70 and 80 kgs. Of course they may feel some stiffness with our road conditions in India. For people like me weighing around 3 digits, the default suspension setting is sufficient enough to do decent high speed riding with added comfort.
Having said that, we changed the suspension setting to comfort mode (without changing the pre-load), but I could see the ride quality becoming slightly softer. With this comfort setting, we did a short TR only on the city roads and not on the highway. So I cannot comment fully on how soft the suspension is with the comfort setting. Probably a back to back TR with S would have cleared our doubts, but I never had issues even with the default settings.
I found the feedback from the suspension/tyres was so good that I could feel the tar laid on the road. I could feel even small undulations, but it never made the bike uncomfortable to ride.
Brakes - An average rider like me can feel 200% confident. Just one finger is enough to apply enough brake pressure to stop the bike. I would say the brakes as the MOST BRILLIANT component in RS. From being a Ninja 650 rider, I cannot not stop appreciating how great the brakes are. Brilliant !!!
Wind blast/drag - Very difficult to encounter the wind as you cross 120 kmph on this bike. I had to literally hold on to the bike by hugging the fuel tank tightly with my legs and rest my chest on the fuel tank. Having a good windscreen is the NEED for this bike.
Intake growl - I like to keep this as a separate para just to describe the beauty of it. I was thrilled with the intake growl of S. With RS, the intake growl has few more decibels added to it. Above 6000 RPM, the intake growl becomes so loud/bassy that it can potentially damage your ears in long run. For potential buyers, it is best to get good helmets which can reduce the noise or start using the ear plugs. It is all FUN to hear the intake growl. In other words,
STREET TRIPLE 765 DEFINES ITSELF PURELY BY ITS INTAKE GROWL.