A lot depends on how it was maintained. 4k miles per year is not a problem as long as it was maintained properly. Oil and filter at least once per year and brake clutch and coolant every 2 years as per the manual. And the brake recall done.
The changes from 2010 to the 2012 model are more than noticeable. Smoother transmission shifting. Suspension
upgrade. Then there is the style change and USB plug in the trunk, just to name a few things.
My 2005 was a great bike. However I like the subtle changes to the 2012 - 2017. My present is a 2016. Since I installed the Henry final drive.... I have lost all interest in the Gen 6. Just my choice.
If the one your looking at was well maintained, I would recommend going for it.
Honda recalled most of the gl1800's for rear brakes locking up. A search for gl1800 rear brake recall will get you the information. Or take the VIN to a dealer and have them run it.
Not all of the bikes had a problem, but it is a recall.
I have a 2012 air bag model that I bought new. I have about 58k miles on it. Had the stumble real bad. Ordered the kit from Electrical Connections to fix that problem. Some 2012's didn't have the stumble problem. No other problems.