So.. just replaced mine at lunchtime with the Napa 9848. Napa gives a 10% AAA discount, be sure to ask for it - even if you're not a member, because they probably won't ask to see your card.
Just realized that my old battery did not have a vent tube attached and none was in sight, and I slapped the new one in without it crossing my mind until now. It was a stock BMW AGM that had been replaced once under the 4/48 warranty. Should a vent tube be there? Should I be concerned leaving it there without one? It's been that way for 3+ years, but... sheesh.