I see nothing wrong with an R3 sportbike but if I was gonna get a 300cc... I'd get a dual sport so you can have 2 bikes in 1....As a stock dual sport, it'll be more suited for off road than street. But if you wanna do more street riding like daily work commutes. Just buy a set of super moto wheels/tires & save your stock wheels/knobby tires for when you wanna go dirt bike riding. The R3 is street only but a 300cc super moto will be just as fast on the street. Or just barely hardly noticeable slower.
I would only get a dual sport if you plan on off roading a lot. I might get a dual sport 250cc soon but would rather have a street bike. From what I've seen most dirt bikes are single cylinder thumpers where the street bikes have 2+ cylinder engines. More cylinders and move valves means a bigger valve area to piston ratio =higher revving and more hp. A brand new KLX300 super moto makes 24 hp while an R3 makes 41.5 hp. An R3 has a top speed of about 112 mph where the Super moto is around 90mph. On the other hand, a dual sport is a lot of fun on more terrain where you would never want to take a street bike.
2 bikes in one would be nice, but off road ain't my thing. I just don't have the cushioning to be comfortable with a bunch of bumps. My spine is very old, and I use the rest of it's time on earth, taking horseback riding vibrations. I don't even go down bumpy roads in my cars. Yeah, dual sports have different gearing, but would get smoked by my R3. Mine is a 321cc. Don't get me wrong, all bikes are nice but I have a certain style that I look for. KTM or Ducati will get my next order most likely.