Odyssey isn't that bad. I looked into your Genesis info above. There is indeed a matching Genesis battery for the PC680, which is the NP18-12 that you can see here:
ENERSYS Genesis NP18-12BFR . Just based on comparing pics/specs/descriptions, I'm pretty sure that's the same internals as the PC680. It's just a different jacket and different terminals, and a little under half the price (~$50 vs ~$115). I'm sure it's a cheaper option for the same thing
electrically, but there is some value in having screwed-in SAE posts and a thicker plastic jacket. Maybe not $65 worth of value, but really the savings there are pretty small potatoes compared to the cost of operating the car over the life of the battery, not to mention all the other related modding you're doing if you care enough to drop battery weight.