I wouldn't, and I've replaced lots of batteries for customer mowers over the years. The AGMs that fit are basically made for ATVs. Unless your mower is subject to an abnormal amount of vibration and abuse, or gets in "wheels up" situations a lot, they aren't worth the money over a standard battery, and you won't see improved battery life for the average homeowner lawn machine. My go-to replacements for customers are whatever Napa, WalMart, or the nearby Autozone has in stock, and I've never been disappointed.
The bottom line is buy the lawn battery with the best warranty and CCA's you can for the money. It's also just as important to make sure your wiring, battery leads, and grounds are good and clean. I've gotten 8 years out of a standard 340 CCA Interstate lawn battery from Home Depot. Granted, it was stored inside and on a garden tractor that is operated year round, but it's still pretty good for the $29.99 I originally paid for it. If your equipment is not used during the winter, disconnect the battery and keep it on the bench in the basement or garage where it's warmer and that alone will help extend it's life.
