Mine is (apparently) bone stock still with 28,000 miles on it. Just lower bars, grab rails, and race tech emulators. Soon I'll install the Ohlins rear shock and Power Commander. Nothing to make it stand out, which is exactly how I like it. Don't have to worry too much about being targeted for theft because it's not a supersport. I just can't get into the looks of the '09 and up. The gauges are horrible too.
It'll do 80 all day on the interstate (or anywhere else) but long highway stints hurt my Achilles, being 6'2". On one leg of my trip to Cedar Point this last weekend, I got 205.5 miles on one tank for 55.35 mpg. Worst I've run is about 47 mpg- which is still about 15-20 mpg better than the I4s I've ridden with. Where they have to refuel after 90-100 miles, I'm perfectly happy to go to 160+ miles when I'm playing, and frequently hit 190 miles on a tank commuting.
State and county roads are a blast- the tighter the better- and it really shines there. I've had saddlebags and a tent and sleeping bag on mine for an overnighter in WV (100+ miles away), and run down US219 as far as it goes then dropped off the bags and hit Deals Gap (700 miles), and just got back from Sandusky (330 miles). Of course, it's just as happy hauling me to work on back roads, or fooling around on the way home. Anything you ask, this bike begs to play. The only other bike I've ridden with all that capability is a Bandit 1250S.
Maintenance is no more than any japanese sportbike. Valve inspection/adjustment every 15,000 miles, oil and tires a bit more often. LOL Replace the brake pads and tires after a full season or more for something with better grip and feel. I don't want to hear any more shit about "Needing more power" after a month or two of riding. If you feel that way, you probably don't belong on a motorcycle.
I have an '07 (1st gen) which I MUCH prefer to the '09 (second gen). I've had the chance to ride an '09 ER-6n (same engine). It really didn't feel any better. The low RPM stutter isn't smoother, it simply feels like the ignition has been retarded. There's no noticeable power difference either. Stock brakes are slightly better, and the suspsension is better matched front to rear. The first gen suspension is very stiff up front, and soft out back. The '06-'08 transmission requires less effort- the '09 felt like it was shifting through molasses.