A friend in the trade told me that 90% of the battery problems they encounter are with the gel type batteries. Though I do have one on my Moto Guzzi, and it's been fine.
I got seven years out of my Dakar original lead acid battery, and probably could have got longer if the bike was in more regular use. Lead acid batteries have been around many years without problems, after all you can't change the laws of physics. They're also half the price!