Yeah, I've noticed that Optima's quality has really gone downhill two. I bought two redtops last summer and one died within a month, the store I bought it from gave me such grief with returning it I gave up and bought a yellow top from Lordco.
From what I've read and heard from others, Optima has been owned and manufactured in China for at least 2-3 years now. And that coincides with when people started to have troubles with the previously long life and reliability of them.
Deka makes good batteries and I've been heard good things about them. I get a work discount at Polar so if I end up replacing my yellowtop as well, I know exactly where I'm getting my next one from. The side posts should put out the same (or near same power), don't see why the won't unless its just a design flaw. Everything GM pretty much uses side posts including the diesel pickups (from what I've seen of them), so why would they not make the side posts up to par? I have my winch mounted to the side posts and it works just fine.
I don't have any real experience in this issue, but upon reading many reviews and stories on other sites and forums, I've concluded that the Optima (and to be fair, many others too) don't have the same current available through the side posts that the top posts do. I don't know how, I don't know why, but when I brought it up with Polar the day I bought the Deka, they concurred too.
LR