I've never had a battery last longer than 4 years in my old airhead. It didn't matter if it was high dollar German made OEM or an el cheapo no name made in Taiwan. Four years and done. Then, 8 years ago I bought an Odyssey. Its still going strong. I don't have power in my garage, so no tender. I do remove it each winter (its easy so if I want to ride in January its 10 minutes to put it back in). Its a 925. I will buy another when it dies. Best motorcycle battery I've ever had.
Lots of airhead GS riders over on Adventurerider use the 680 with good success. I bought the bigger and heavier 925 because I have never, not once in my life, been in a situation where I wished I had
less battery capacity. I have, however, been in situations where I wished I had more