I've gone through five Optima Yellow tops over the years and had mixed experiences with them. The first two lived full lives (5+ years) but the last three only lasted for one to two years per battery. In Optima's defense, the last two were warranty replacements. We live in the high desert southwest and winter lows can get into the single digits and summer highs get into the 100's so life can can be tough on batteries out here.
The hype around the Optimas was enough to make me want to try them but my experience with the last three batteries over a four year period made me dig a little deeper into battery types and specs.
I ended up switching to the Die Hard Platinum group 65 from Sears:
http://www.sears.com/shc/s/p_10153_...tive&cName=Batteries&sName=Car Batteriesmv=rr . It's actually an Odyssey PC-1750 battery repackaged with a gray Die Hard case and 4/8 year warranty instead of Odyssey's two year warranty. It also cost about $100 less than the Odyssey. Odyssey originally designed the PC line to comply with military application standards as well as commercial markets. They are Optima's #1 competitor for AGM deep discharge batteries.
I won't blather on about why the Die Hard/Odysseys seem to be technically superior; you can probably find the same information yourself if you are interested. What I will say is that the Die Hard Platinum is now the battery of choice in the rokdaddy fleet. Low internal resistance, excellent capacity per volume, great reputation, solid warranty and nationwide support.
I'm hoping that this will be the "end all" battery for me but I'll need to run through a few of them before I know for sure.
-Rok