I'm in the market for a new AGM battery and noticed most of the parts stores sell roughly the same Johnson Controls re-branded AGM battery. Advance Auto was in the lead because of the readily available online coupons. Their battery has a 3yr free replacement, which is pretty good. I then noticed Pep Boys has a Champion branded AGM that also appears to be made by JC. Their warranty is 4 years free replacement though. Pep Boys is currently running 25% off online + an additional $40 MIR for the Champion AGMs. That brings my total to $190 - 25% = $142.5 - $40MIR = $102.50 before tax. Installation is also free if you want to go that route.
That seems to be the best deal going right now for an AGM and also one of the better warranties to boot.
Working rebate link:
...or submit rebate online: