I have a 4000W Coleman generator, a MTD lawn tractor, and a John Deere Gator that are all in their 20's in age. When new battery time comes, is there a downside (or an upside) to getting AGM batteries? I've read that standard lead-acid chargers will damage AGM batteries; true? Any tips appreciated. I guess the claim is that AGM batteries last longer; is it worth it?