Here's my totally unscientific, anecdotal comment:

I've had/used a classic for 2+ years. Never had a functional problem. Never got sick from the water I treated with it. Used it for 4 days and had plenty of battery juice left. I always take extreme care to store it in my pack and to avoid dropping it. I'm noticing a bit or corrosion on one of the electrodes, probably because I didn't dry it completely after use. It's not the lightest/simplest option but it has its niche.