I've had mine since May 08 and believe the battery's life is lower than it should be, but so far it's cranking just fine. I monitor voltage with the Scangauge constantly and if I leave it for 2 hours or so, the voltage drops from 12.5 to 11.5, in the cold weather it's down as far as 11.1 volts if the auto lights turn on just before I crank in the morning. I'm pretty sure those same numbers were higher a few months ago, but can't tell if it's due to cold weather or battery age.
If it ever drops below 11 volts, I'll go get a load test. It's too cold this week to justify. I'm planning a trip to the dealer (300 miles away) to get 10k service done early, so I'll have them check it also. It's a $50 battery. If it dies, I know what to get: Optima 78/34. May as well upgrade while I can, right?
But yeah, Smart's realizing they made a mistake on the batteries and I expect they'll fix that in the future.