Join Date: Jan 2016
Location: Seattle, Wa. USA
This probably won't be helpful, but... my 2 cents.
I'm a new DL650 owner, so... not too experienced with the former models, but I test rode a preowned and heavily modded 2009 and a 2011 (both old body style) before buying a 2015 650 with 0 miles. Got a solid price and financing. Between the 3 bikes I test rode, the rides all felt pretty much the same. It's my understanding (someone correct me if I'm wrong, please) that there aren't too many differences other than the updated body style and the digital instrument dash.
The older bikes I looked at had aftermarket windshields (buffeting at speed has seemed to be a consistent issue across model years), hand guards, engine guards, skid plates, hand warmers, :|:|:|:|ing amp meters, center stands.... a ton of extras. I thought these additions were what I wanted, but their installations were done by the owners and didn't look very well done. I went with the stock 2015 because I didn't want to have to reverse engineer all those (electrical) additions if they ever failed. Plus, new bike. It's mine and I don't have to guess at how it's been treated in the past.
Not sure what the diff's are between 11 and 12. Test ride em! Good luck!