Just do a -1. You'll want to buy a speedo healer as your speedo will will go from being 6% off to around 13% off. Most of what you'll notice in a -1 will be a reduction in the amount you have to slip the clutch to get the bike moving from a stop. You'll also notice an appreciable gain in 6th gear rolling on the throttle at hwy speeds. The bike will go from being at 5k rpm to around 5500K rpm at cruising speed. If you look at the dyno chart you'll notice a decent gain in HP going up 500 RPM. So, it will feel more snappy rolling on the throttle. I also run the +2 in the rear, and it makes it really nice, putting the bike in the powerband right around 6k RPM or just under around 75-80mph. So when cruisind on the freeway, I've got a noticeable increase in the amount of pull when rolling on the throttle in 6th gear as compared to stock.
Asain, in 1st gear, much better acceleration off the line too. Instead of the bike lifting the front end at 9.5k rpm in 1st, Now it lifts the wheel at 6.5k rpm when holding open the throttle, not whacking it open.
Anyway, def do the -1, just understand that a $20 sprocket when you add a speedo-healer will actually cost you $130. Plus install on both items, which is simple enough.