Big Crank EXT30L is a good AGM replacement for about $113, made in the USA. Mega Crank MTX-30L is a little cheaper at about $100, made in China. Both are from Batterymart.com. I bought Mega Crank last year and it has held up very well so far.
Right now, AMAZON has the DEKA EXT30L on sale for $109.15 while supplies last with free shipping.
DEKA makes the Big Crank so this is a better deal. DEKA is made in USA, I think in PA.
I am using the Odessey (I believe the PC925 model) in my 2011 RXT 260 iS. The battery is eleven years old (I was using it in my previous ski) and still going strong. The Odesseys are expensive but they apparently last for a long time. I charge it on a Battery Tender every two weeks all year long.