My first bike was a 650, I switched to a "sport-tourer" (Suzuki V-Strom), bought two more & owned 3 for a couple of years, added a KTM SuperDuke (Naked Streetfighter?)... eventually sold it cause it was fun for up till 3-4 hrs. but not so much for 8 hr. days.
Don't underestimate 650's... many bike/ rider combo's are all bike & little or no rider.
Couldn't tell you how many sportbikes we used to pass on Fort Mtn, Deals Gap (The Dragons Tail), & the Nantahala Skyway.
On long straightaways the faster sport bikes would pull ahead (except when I was riding the SuperDuke)... but we would almost always catch them in the twisties.
We quit the childish stuff as we realized how ignorant it was (too much to lose & nothing to gain) but in addition to really good road manners, lower initial price, & excellent fuel economy, the 650's have plenty of power for most legal riding needs.
